There was also the penchant for having cartoons of real people becoming superheroes. Like the Harlem Globetrotters and Muhammad Ali.
I definitely remember the Globetrotters one. From what I remember of the characterisation, it'd not be shown today because of modern sensitivities to such things. (At least as a kids' cartoon, although it might scrape through in a nostalgia/"hey wasn't the TV we had back then so strange!" slot. Don't remember the Ali one, so no idea if that'd have the same issue (or just that it'd now have less topicality/brand-recognition for the target audience, and be less than the shiny-shiny CGI-assisted animation of the equivalent modern output).
Apparently it was sort of like Scooby-Doo (mystery monster of the week who is really just Farmer Jenkins in a mask). I'm kinda hoping that where it differed was that Ali just beat the shit out of them instead of running around with wacky hijinks, but that would make for a pretty short cartoon.
I don't think I ever saw the Ali cartoon, but a lot of these "real people as cartoon people solving Scooby-Doo-like mysteries" cartoons were spin-offs of Scooby Doo itself, which went through a couple seasons with a guest star every week. The cartoon Harlem Globetrotters started as guest stars on Scooby Doo, for example. So did a couple fictional people from old live-action TV shows and movies that might have otherwise been forgotten. So, Charlie Chan was a guest star on scooby Doo, then got his own series, The Amazing Chan and the Chan Clan, which was a cross between Scooby Doo and Josie and the Pussycats. The Addams Family appeared as Scooby guest stars, then got their own show which wasn't mystery-oriented, but more like the original series. And then they wound up in stone-age form on the Pebbles and Bamm-Bamm show. Saturday morning TV was weird.
I actually remember a huge amount of TV from the '70s, including prime time shows, specials, and made for TV movies, if anyone needs any assistance. I pretty much tried to watch one episode of just about everything, although I tended to avoid the dramas and focused on sit-coms and sci-fi. I was the only kid ever who spent his allowance on the yearly TV Guide fall season preview, to prepare my TV watching for the next year. I, too, was weird.