Many of the new plants and foods have power-up effects when eaten, boosting one or several stats ranging from the simple mushrooms (20% increase to recuperation) to powerful drinks like the Frog-people's Power Blast (doubles attack power, plus gives the eater the ability to buff two allies with the same effect).  Most power-ups last one in-game month, which means that based on the normal 'hunger' rates (which cause them to eat about once every one-and-a-half months), a creature will have one power-up active at a time.  It's tough to try and control who gets boosted with what and when, but if you keep a well-stocked pantry with high-level power-up foods, your citizens will be better workers and your soldiers will be better fighters overall.

Regular Plants

Apple: Edible, brewable, and cakeable into apple pie.
Banana: Edible, brewable, and cakeable into banana cake.
Grape: Edible, brewable, and cakeable into grape tarts.
Watermelon: Edible and brewable.
Fuzzbush: A thread plant.
Melon: Edible, brewable, and cakeable into Yoshi Cookies, which will power-up Yoshis if they eat one.
Wheat: Milled into wheat flour, an important cooking ingredient.  Can also be brewed into beer.
Rice: Grows in wet areas, and can be milled into rice flour or brewed into sake.
Sugar Cane: Milled into cane sugar, an important component of cake.
Sugar Beet: The temperate version of Sugar Cane, used as a sugar source.
Iced Potato: A hardy winter crop that grows fast in the tundra and temperate regions.  Edible, millable into iced potato flour and brewable into iced potato vodka.
Turtle Bush: Brewable into Koopa Tea and produces Turtleaves, which are cakeable into Koopa Dumplings.
Strange Bush: Grows in Evil regions.  Produces Strange Leaves which make the eater dizzy, cakeable into Strange Cake which also makes the eater dizzy, and cookable into Dizzy Dials which give the eater the power to make enemies dizzy.
Subcon Vegetable: Doesn't grow anywhere in the wild.  Only Shyguys can gather them from Subspace Portals.  Brewable into subcon spirits.
Berry: Found all over the place.  A staple food-plant.
Strawberry: A common fruit that grows in most areas.  A basic cake ingredient.
Red Berry: Grows in Good regions.  Brewable, cakeable into big cookies, and can be milled for red dye.
Blue Berry: Grows in Good regions.  Brewable, cakeable into big cookies, and can be milled for blue dye.
Yellow Berry: Grows in Good regions.  Brewable, cakeable into big cookies, and can be milled for yellow dye.
Stinky Herb: Grows only in Good regions, but basically unremarkable.  Edible when cooked.
Crystal Berry: Grows only in Good regions.  Useless but fetches a nice price.
Mango: Edible and brewable.
Peach: Edible, brewable, and cakeable into peach tarts.
Chuckola Fruit: Comes in three colors, all of which are functionally identical.  Edible and brewable into Chuckola Cola.

Low-level Power-up Plants

Mushroom: Recuperation +20%.  Cakeable into Shroom Cake.
Mid Mushroom: Recuperation +50%.  Cakeable into Shroom Cake.
Max Mushroom: Recuperation +100%.  Cakeable into Shroom Cake.
Honey Pod: Grows in Good regions.  Cakeable into Honey Candy.  Produces Honey Syrup - Endurance +20%
Maple Pod: Grows in Good regions.  Cakeable into Honey Candy.  Produces Maple Syrup - Endurance +50%
Royal Pod: Grows in Good regions.  Cakeable into Honey Candy.  Produces Royal Syrup - Endurance +100%  (Thinking about it now, are honey syrup and royal syrup intended to be bee products?)
Red Pepper: Strength +20%
Green Pepper: Toughness +20%
Blue Pepper: Agility +20%

High-level Power-up Plants (these take about a half a year to grow and don't spread easily, but grant special powers.  Toads can seal them in blocks to save them for later.  Adventurers will want to keep an eye out for these.)

Super Mushroom: Turns you into a giant and doubles strength and toughness.  Is planted in the spring and harvested in the autumn.
Fire Flower: Gives you the power to throw fireballs.  Could be hazardous in Fortress Mode, but lots of fun as an adventurer.  Can also be used to extract Hot Sauce.  Planted in the winter and harvested in the summer.
Ice Flower: Gives you the ability to spray icy vapor.  Use 'antifreeze' before using it to make yourself resistant to self-freezing.  A little bit of a hazard to CPU controlled creatures.  Planted in the summer and harvested in the winter.
Volt Shroom: Gives you a short-range lightning attack.  Planted in spring, harvested in autumn.
Super Bush: Its Super Leaves will transform you into a Tanooki when eaten.  Planted in spring and harvested in autumn.
Mega Mushroom: Like Super Mushrooms, only more so.  Puts a creature on near-megabeast scales of size and strength for a month.  Very rare though...
1Up Mushroom: For a short while after eating it, you get the power to escape from pretty much any situation.  Can be used to regrow lost body parts in Fortress Mode and may save your hide in Adventure Mode.

Frog People Specials: Brewed from special rare herbs found in swampy areas.  Generally, you'll get them by trading with Frog People.  They're expensive, but very powerful.

Froggie Drink: Recuperation +20%, plus the drinker gains the ability to buff two allies with the same bonus (even if they already have a powerup).
Frog Elixir: Like Froggie Drink, but with Recuperation +50%
Frog Megalixer: Like Froggie Drink, but with Recuperation +100%
KeroKeroCola: Recuperation +100% AND Endurance +100% AND can be passed on to two allies.
Bracer: Toughness +100%
Energizer: Strength +100%
Crystalline: Toughness +100% and can be passed to two allies.
Power Drink: Strength +100% and can be passed to two allies.

Fry an Egg:
Any egg -> Fried Egg

Make Pasta:
Flour* -> Dried Pasta

Cook an Item:
Fried Egg -> Omlette
Dried Pasta -> Fresh Pasta
Strange Leaf -> Dizzy Dial
Mild Cocoa Bean -> Chocolate
Yoshi Gland -> Yoshi Candy

Make Pasta Dish (Item+Dried Pasta):
Fresh Pasta -> Lotsa Spaghetti!
Mild Cocoa Bean -> Chocolate Pasta
Koopa Leaf -> Koopasta
Hot Sauce -> Spicy Pasta

Cook with Meat (Item+any meat):
Dried Pasta -> Meat Pasta
Mango -> Fruity Hamburger
Peachy Peach -> Fruity Hamburger
Fried Egg -> Fried Egg Dog

Make Cakes and Pastries (Item+flour*, sugar*, and fresh egg):
Fried Egg -> Big Cookie
Berry -> Big Cookie
Red/Yellow/Blue Berry -> Big Cookie
Dried Pasta -> Pasta Cake
Sweet Strawberry -> Tasty Cake
Hot Sauce -> Fire Pop
Strange Leaf -> Strange Cake
Apple -> Apple Pie
Banana -> Banana Cake
Grape -> Grape Tart
Peachy Peach -> Peach Tart
Melon -> Yoshi Cookie
Koopa Leaf -> Koopa Dumpling
Mild Cocoa Bean -> Chocolate Cake
Any basic Mushroom -> Shroom Cake (warning: will lower the effectiveness of Max Mushrooms)
Any basic Syrup -> Honey Candy (warning: will lower the effectiveness of Royal Syrup)
Horsetail -> Horsetail Tart
Yoshi Extract -> Yoshi Candy

Surprise Cake (3x more flour, sugar, eggs, any cakeable ingredients, plus one of any available item):
? ? ?

* Vanilla plants' flour and sugar do not work for these reactions, only wheat flour, rice flour, iced potato flour, cane sugar, and beet sugar will be used.

Firebrand: Throw fireballs forever!  Yay!  Can also unleash Firey Finale, for those times when you just need to torch everything.
Thunderhand: Shock enemies to stun and damage them.  Some powerful enemies are especially vulnerable to it.  Can also temporarily grant allies the ability to use a close-range version of the same attack.
Blizzard: Gives you the ability to use a freezing spray.  Use 'antifreeze' to protect yourself from freezing and 'clean' to get rid of potentially hazardous residue.  Also comes with extravision to deal with potentially frozen eyeballs.
Vibe: Gives you the ability to use four short-term stat altering abilities, on yourself, your allies, or your enemies.  Rage doubles strength and halves toughness, Gloom doubles toughness and halves strength, Calm doubles recuperation and halves agility, and Joy doubles agility and halves recuperation.  Each creature can have only one 'vibe' active at a time.
Wizard: Gain the ability to damage enemies from a distance, 'teleport' (speed up for a short period but become unable to harm enemies while doing so) and polymorph enemies into weaker forms.  They can also raise the dead and will build towers in worldgen.  However, creatures who learn it will no longer gain physical strength, and their muscles will atrophy over time, so wizards tend to be weak physically.  Koopas can produce potions that turn them into Wizards in fortress mode, minus the necromancy.
3-Up Moon: Grants you the ability to use a 1-Up mushroom ability three times a month.  It won't actually revive you if you die, but it will allow you to escape from pretty much any situation fully restored.  You'll be happy you had it if you find yourself lying at the bottom of a pool of magma without any limbs.

Giant (Curse): Doubles your size, strength, and toughness permanently.
Tanooki (Curse): Transforms you into a flying, at-peace-with-wildlife Tanooki permanently.  You also gain the ability to vanish before the eyes of your enemies.  As a side effect, this renders you immune to polymorph spells and mushroomization.
Metal (Curse): Transforms you into a nigh-invincible metal elemental, and also renders you immune to transformation.  What's with these curses anyway?

Firemetal: Needs to be extracted in strands, much like adamantine, and like adamantine it can be woven into soft clothing or made into armor.  It maintains a constant level of heat, making it fireproof.
Hoohoo Blocks: A hard and heavy metal.  Not great for bladed weapons but makes excellent hammers.

Domestic creatures:
Moo Moo/Debull: A cow by any other name...
Sleepy Sheep/Snooze Ewe: A sheep that can put its enemies to sleep.
Li'l Oink: A pig that produces eggs and comes in many colors.
Beanlet: A small, trainable, vermin-eating bean-like pet.
Shellcreeper: A large turtle that can hide in its shell for defense.  Trainable pets for koopas, and their shells can be harvested when you butcher them.
Parashellcreeper: A variety of shellcreeper that is capable of flight.
Spiny: A relative of the shellcreeper with a spike-covered shell.  It can use its spines for attack, and they can be used to decorate items when it is butchered.
Buzzy Beetle: A shellcreeper relative with a shell of solid bronze.  It is nearly invincible to unarmed attacks when it pulls itself inside.  Its shell can be harvested and smelted into bronze bars by the Koopas.
Paraspiny, parabeetle, sky-blue spiny, and sky-blue paraspiny are all various combinations of the various shellcreeper types.  Sky-blue paraspinies are the rarest, with spiny, metal, winged shells.
Lakitu's Cloud: A small cloud used as a flying mount by Koopas.
Chomp: Large, iron-shelled balls with teeth, found underground and domesticated by koopas.  They are the ultimate guard dogs, capable of tearing apart most enemies in seconds and can even take on some forgotten beasts when fully grown.  However, their low speed and poor eyesight makes them ineffective for most other purposes.  They also have poor endurance and frequently collapse from exhaustion if attacked by multiple opponents at once, and are unable to swim.  If you choose to butcher one, its shell can be smelted into a great deal of iron bars by the koopas.  Vulnerable to lightning.
Stone Chomp: Magically-animated boulders with teeth.  They are sterile and not as tough as their organic/metal counterparts, but are still pretty much indestructable to anyone attacking bare-handed.  They make a more affordable embark creature to defend your fortress against early yoshi attacks.  Sometimes you'll find them guarding tombs.

Regular creatures:
Nipper Plant: Grow into piranha plants if they remain on the map for long enough.
Piranha Plant: A stationary, carnivourous plant.
Mobile Piranha Plant: A mobile carnivorous plant.
Jumping Piranha Plant: A flying carnivorous plant.
Venus Fire Trap: A fire-breathing pirahna plant.  Very dangerous.
Pirahnacus Giganticus: A huge pirahna plant that lives in savage regions.
Monty Mole: Throws mud rocks at passerby and then hides.  Extremely annoying.
Buzzer: Poisonous sting attack.  May attack unprovoked.
K-9: Large predator.  Can inflict 'Fear' status.
Porcupo: Large spiny mammal.
Spikey: Biped with a spiked shell.
Frogog: Large predator.  Secretes contact poison.
Fighter Fly: Flying creature that punches and kicks.  Prone to rage.
Arachne: Large poisonous spiders.
Koopeleon: Can become invisible.
Artichoker: Large ambush predator.  Uses electric attacks and toxic stench.
Carroboscis: Large ambush predator.  Can inflict Fear, Silence, and Mushroomization.
Beanie: Weak plant creature.
Parabeanie: A flying beanie.
Pestnut: Plant-based creature with a full-body spiked shell.
Troopea: Plant-based shelled quadruped.  Can increase recuperation of other plant-based creatures.
Paratroopea: Flying troopea.
Sharpea: Plant-based spiked creature.
Giant Shellcreeper/Parashellcreeper: They live in the savage regions.
Rex: A large predatory dinosaur with a horn on its head.
Dino-Rhino: A large herbivorous dinosaur.  Transforms into small, fire-breathing Dino-Torch when injured.
Reznor: A fire-spitting, three-horned dinosaur.  Trainable.
Ukiki: Mischievous and will steal food and items.  Trainable.
Wiggler: Prone to rage.  Found in forests.
Fuzzy: Classified as 'large predator' despite their small size.  Attack in swarms and can suck blood.
Scutlet: Appear in large groups.  Not particularly threatening.
Sockop: Tough plant-like carnivore.  Produces strong leather.
Treevil: Large wooden predators.  Tough to kill.
Guerilla: Large primate.  Strong but docile.
Amanita: Can Mushroomize its victims.
Winkle: Large talking snails.
Gecko: Poisonous bite.  Will randomly go berserk.
Puff: A small cloud-like creature.
Milde: Harmless tropical puffballs.
Tap-Tap: Has a copper shell.  Koopas can smelt them into copper bars.
Dayzee: Found in Good-aligned areas.  Rare Amayzee Dayzees are surprisingly lethal.
Poochy: An amazingly durable, large-sized dog.  Benign but very tough to kill.  It can be trained for hunting.
Huffin' Puffin: Large tropical flightless birds.
Goonie: Tropical bird.
Raven: Tropical flightless bird.
Grinder: A large tropical monkey that will steal food.
Snapjaw: Large crocodilian predator.
Puni: Small intelligent creature found in Good-aligned forests.
Jabbi: Small blood-drinking creature found in Good-aligned forests.
Pider: Spits webs.  Found in good-aligned forests.
Lunge Fish: Lives in the tropical swamps.  Extremely dangerous and aggressive.
Spray Fish: Can spray water and knock its targets into the river.
Frog Pirate: A huge frog that lives in tropical wetlands.  They will show up in groups to raid your food stores.
Cheep-Cheep: Common large fish.  Can be hazardous to fishermen.
Trouter: Common large fish.  Can be hazardous to fishermen.
Deep-Cheep: A large oceanic fish.  They are more aggressive than their inland counterparts.
Boss Bass: An enormous cheep-cheep that lives in oceans.  They are aggressive and very dangerous.
Blurp: A docile fish living in tropical regions.
Sidestepper: Found on beaches.  Prone to rage.
Clawgrip: Giant sidestepper variant.
Blooper: Flying oceanic squid.  Can squirt ink.
Sushi: Benign oceanic predator.
Manta: Enormous, docile manta rays that live in the open ocean.  They can be used as exotic mounts.
Unagi: Predatory oceanic eel.
Pokey: Cactus-like desert creature.  Produces pokey fruits when butchered.
Klepto: Flying item thief.  Lives in deserts.
Cobrat: Spits bullets.  Lives in deserts.
Muncher: Metal-shelled carnivorous plant.  Lives in deserts and tundra.
Panser: Fire-breathing mobile plant.  Found in savage tropics.
Gao: Fire-breathing lion.  Found in savage deserts.
Nyololin: Fire-breathing snake.  Found in savage deserts.
Bunbun: Giant bee.  Found in savage deserts.
Ganchan: Living boulders.  Invincible but fortunately not aggressive.  Found in savage wastelands.
Scuttlebug: Spins webs.  Found underground and in forests.
Cleft: A durable stone creature that lives on mountains.
Mega Mole: Powerful underground creature.
Ninji: Mischievous.  An intelligent pet.
Rat Funk: Cave-dweller.  Has a poisonous tail.
Whacka: A rare creature found in mountains.  When hit in the head, it produces valuable, edible 'bumps'.
Swooper: A large bat.
Fangs: Another kind of large bat.
Lemon Drop: Harmless cave dweller.
Enigma: Cave-dweller.
Ameboid: Can multiply if attacked with bladed weapons.
Sparky: Blind but agile cave-dweller.  Moves rapidly but without direction.
Dorrie: Underground water-dweller.  Large and docile.
Gloomba: Hidden underground tribal goomba variant.  Somewhat tougher than above-ground goombas.
Burt: Cave-dwellers.  Drop silk trousers when butchered.
Lantern Ghost: Cave-dwellers.  Drop silk cloth and lanterns when butchered.
Birdo: A rare dinosaur, capable of sucking blood and spitting eggs.  Can be tamed.  Like Yoshis, both males and females will lay eggs.
Hot Lips: Dangerous magma-dweller that can spray magma mist, but only when submerged in the magma itself.
Podoboo: An animated blob of magma.  Extremely dangerous in a melee, as it tends to splatter magma around it.  It can be tamed, but is still very dangerous if not handled with extreme care.
Blargg: A giant predator made of magma.  It is easily damaged, but can do a great deal of harm before it's destroyed.
Magmite: Magma-dweller with a firemetal shell.
Thwomp: A huge, animated stone block that lives in volcanoes.  It moves slowly but its slamming attack will shatter pretty much whatever body part it hits.
Bully: A hard-shelled creature that lives near magma pools and will attack any creature that comes near.  It's mostly up to luck who falls into the magma first.
Big Bully: A larger version of the bully.  It is heavy enough to cause injuries in its own right.
Formless: Cave-dweller.  Invincible unless attacked by a non-physical means such as fire or lightning.  A successful attack turns it into Mokura.  Mokura itself uses lightning, cold, and poison to attack, and grants a disproportionate amount of skill leveling when attacked.
Spike: Attacks by spitting spiked balls.
Mr I: Found in evil regions.  Immobile, but very hard to kill and can shoot at passerby.
Flurry: A small snowman found on glaciers.  Easily killed.
Mr. Blizzard: A larger snowman.  Throws snowballs to attack.
Moneybag: A strange creature made of cloth and containing a gold bar inside it.  Found in cold climates.  If you tame one, it will sometimes lay gold bars in nest boxes.
Ostro: An ostrich that can be used as a mount or wagon puller.
Albatoss: A large bird of prey.  Some creatures will use them as mounts.
Gnawty: Bipedal beavers.
Klaptrap: Small crocodiles.
Zinger: Giant bees.  No poison but have large stingers.
Flitter: Large dragonflies.  Excellent observational skills, so make good guards.
Neek: Large rats.
Necky: Predatory bird.  Spits coconuts.

Vermin:
Buzzbee: Basically a bee.  Produces honey, wax, etc.
Beetle: Vermin creature.  Comes in three varieties: Male, Female, and Gold.  The rare gold beetles fetch a high price if sold.
Cricket: Can be processed into Cricket Jam, which can be cooked (by Toads) into Cricket Pie.
Butterfly: A purple butterfly vermin.
Blue Fish: Just something for fishermen to catch.
Virus: A type of vermin that comes in three varieties: Fever, Cold, and Weird.  They show up in large swarms and can infect your citizens.  Though not fatal, it's best to avoid them if possible.
Dudim Phrekenoutonthis: Also known as 'fuzzies', but not related to the other creature called 'fuzzies'.  Strange puffballs that appear in huge swarms.  If you touch one, you'll get dizzy.
Melody Frogs: Come in 12 varieties: C, D, E, F, G, A, B, Soprano, Alto, Tenor, Baritone, and Bass.
Starman: Extremely rare and extremely valuable vermin creature.  Its 'sting' will turn the affected creature into a one-man army for about two in-game weeks, capable of defeating a siege single-handedly (note: fire will still kill them if they aren't holding a shield).  They can be captured with a 'catch live land animal' command and stored for later emergencies.

Night Creatures:
Boo: A ghost that will attack adventurers at night and also appears naturally in haunted regions.  It has the ability to vanish into thin air when it is in danger.
Machine: Created when a regular creature is infected by nanobots, usually as a result of getting into a fight with a Machine Scout.  These mechanized creatures are immortal, extremely durable in their normal form (about as hard as steel), and can reveal their true forms, turning into giant killer robots.  Transforming is permanent and will automatically make you the enemy of all civilizations except the Machine Mades.
Duplighosts: In-story, these are shapeshifters that turn their victims into shadowy doppelgangers and, in turn, steal their bodies and take over their lives as duplighosts.  In practice, Shadowy Doppelgangers will turn their victims into hidden duplighosts, which can transform (for a short period) into a flying duplighost form at will, and will also do so once a month.  If you are playing as a hidden duplighost, selecting 'discard physical body' will transform you permanently into a shadowy doppelganger.
Shadow Siren: Spouse-converters.  They will each pick one of three elemental abilities: fire, ice, or lightning, and will use that element to attack.

Megabeasts
Demon Koopa: A megabeast that tends to take over Koopa civilizations.  It is the size of a demon, magma-proof, fire-breathing, and capable of hiding in its spiked shell (not that it generally needs to).
Giant Chomp: Basically just a chomp, but much, much bigger.  Absurdly powerful and durable but have all of the weaknesses of a regular chomp: poor speed, eyesight, and endurance, weakness to lightning, and inability to swim.  But a single bite will end pretty much all creatures, so watch out.  If you can trap it, it can be tamed just like a regular chomp.  If you manage to defeat it, or manage to capture it and somehow decide that you'd rather slaughter it than keep it as a virtually invincible guard, and are playing as Koopas, you can melt down its shell for more iron than you'll ever need.
Belome: A powerful canine that will try to slurp you to death.  It can also scatter dust that inflicts the 'scarecrow' status, preventing you from using basic attacks.  (Special techniques and magic can still be used.)  Vulnerable to lightning.
Mouser: Uses explosions to attack.  Has an iron skeleton to resist its own explosions.
Triclyde: A three-headed, fire-spitting giant snake.  It can shoot one fireball for each remaining head for a rapid-fire attack.
Angry Sun: A creature that lives in deserts.  It is a glass cannon, able to incinerate entire fortresses but can be taken out with a well-aimed punch.  Not that the puncher will live to tell about it.  Since they don't reproduce, they tend to go extinct within the first hundred years of worldgen, although they often have rather extensive kill lists.
Boss Piranha: Giant-sized mobile piranha plant.  Can spit poisonous goop as well.
Naval Piranha: Semimegabeast that shows up in underground lakes.  It will endlessly spawn waves of piranha plants until it is killed.  As it is aquatic, this can be rather difficult to do...
Great Dragon: Although it has only regular fire, these dragons are more durable than the vanilla DF variety, as they don't bleed easily.  If a large dragon is dunked into magma, it may lose its skin and flesh and emerge as a bone dragon, which feels no pain and has no blood to spill.  The only means of killing a bone dragon is by removing the head or destroying the brain.

There are also some 'Special' creatures that will only appear under specific circumstances.  Have Fun finding them!

Ameboid, a creature that multiplies if attacked with bladed weapons
Whacka, a creature that spawns edible 'bumps' if abused without killing it
Naval Pirahna, a 'spawner' megabeast that produces waves of monsters and limits itself somewhat to prevent overcrowding
Dragons that can have the flesh boiled off of their bones and go on living as a skeleton
Smithy, a boss that shapeshifts between several forms during a single fight and is killed by gradually overheating as he is attacked
Yoshi Glands and Red Yoshi Glands, 'plants' that sometimes (but not always) appear inside fully-grown creatures, and a syndrome that can increase the probability of finding one

0.01: Release. Three main races, a few powerups and secrets, and many creatures included. Shyguys can create subspace portals, and Koopas can create shell armor.
0.02: Lots of new content added: Powerup plants, new secrets, trader races and some cooking reactions for Toads. Koopas will be ruled by megabeasts or demons.
0.03: Toads can dig for resources, but they won't gain skill in mining or engraving. Shyguys no longer produce worthless crafts from portals. Some plant prices altered.
0.04: Magikoopa Sanctum added. Koopas can now produce magic scepters and learn three special abilities for the cost of one large gem each. Teleport secret added.
Major update - 0.1: Toads and Koopas have new underground behavior, new kitchen reactions for Toads, Magikoopa system greatly improved, new plants and animals, traders fixed, general bug fixes.
0.11: More races and creatures, including endgame special enemies.  Toads given metal weapons and castles for Adventure Mode, Koopas can withdraw into their armor in Adventure Mode.  Minor weapon tweaks - chomp shells re-balanced.  Yoshis now eat from stockpiles in Fortress Mode, frog drinks changed to alcohol.  Toads made slightly tougher and heal slightly slower.
0.12: Trading races organized, cooking reactions fixed, new plants and animals added, Adventure Mode races can be played as civ members (as opposed to outsiders).
0.13: Human civ added, warp pipe added, new creatures, animate corpse reaction can now animate an entire room, general bug fixes.
0.2: More creatures added, vibe secret added.
0.21: Shamans and Star Sprites added as 'secret keepers'.  Many special interactions improved or revamped, new megabeasts added.  Worldgen now operates without the need for vanilla creatures, entities, or plants.
0.22: New creatures added to fill up the temperate grassland biomes.
0.23: Power Stars and the Beacon for Toads, Koopas can smelt the shells of metal creatures, Shy Guys can create bonfires and can produce Subcon Crystals. All playable races now have specialties in Adventure Mode. Civs more focused on specific biomes. Many new creatures added.
0.24: Entity territories improved, more creatures including hint blocks added.
0.25: Some interaction/syndrome timing modified somewhat to make them more balanced in adventure mode.  Kong and Kremling civs, a couple new wild animals, some power-up plants and corresponding secrets, phantos, chomp mummies, duplighosts, hidden machines, shadow sirens, and an experimental Shadow Queen interaction have been added.
0.26: Fully shapeshifting Smithy, powerup sealing reaction for Toads, minor tweaks.
0.27: New embark/trader/diplomat messages, couple of new creatures added, Smithy and Shadow Queen adjusted, subspace materials decay over time, some secrets will level up.

ArkFallen for suggesting a means to make Demon Koopas work
Pikdome for early creature suggestions
StephanReiken for plant and domestic animal suggestions
Pokon for civilization suggestions
EmeraldWind for languages and graphics work
Toady One for creating Dwarf Fortress
Shigeru Miyamoto for creating the Mario series
Everyone who tested and offered feedback or suggestions

Rarely in Adventure Mode, you will come across a creature that is immune to all physical damage, although they can somehow still be stunned from attacks.  If you encounter one of these, just avoid it, as they aren't any faster or stronger than normal members of their species.  Wrestling and strangling can stun these creatures, though they don't seem to die from it.

Toads in Adventure Mode will occasionally be dizzy when you find them.  My guess is that the game generates creatures a random level of cave adaptation.  If you want to recruit one, just travel around for a bit and it'll wear off on its own.

While playing as Toads, sometime's you'll get messages saying that someone was interrupted by someone's corpse or body part.  This is just a result of the Yoshi's creature eating mechanism.

If you have piranha plants on your map, they may prevent other creatures from spawning until they are all killed.  Depending on your playing style and the creatures inhabiting your location, this may be a good thing or a bad thing.

Civilian Koopas encountering shellcreepers and their relatives can run into problems as both creatures duck and hide in their shells, unable to move and potentially starving to death.  You'll have to send a squad out to kill the offending creature.