Why Isn't There A Game for That? [Update '25]

I wrote the original version of this post in 2014, then I updated it in 2019. It's probably time to check back in and see how the rpg landscape is changed. There are a number of genres/subgenres that are under-utilized or not utilized at all in rpgs, despite the fact they would probably work pretty well. Here are the ones I listed originally and have been following up on:

Humorous Adventure Pulp
Basically this would cover the whimsical, fantastical, and often violent world of Thimble Theatre (later Popeye) and the Fleischer Popeye cartoon. A lot of fist-fights, fewer guns. This would also cover Little Orphan Annie, various kid gang comics, and (on the more violent end) Dick Tracy.
Update: Still nothing, really. Acheron Game's Helluva Town does a sort of Roger Rabbit or Cool World sort of setting, so references things like Popeye, but it's not quite the same thing.

Wainscot Fantasy
Little creatures hiding in the big world. Think The Borrowers, The Littles, and Fraggle Rock.
Update:  Some progress here! Household by Two Little Mice does this sort of thing, though from its specifically about fairies. There's also a game called Pixies and one called Under the Floorboards that specifically namechecks The Borrowers.

Kid Mystery Solvers
Scooby Doo is probably the most well-known example, but you've got several Hanna-Barbera returns to the same concept. Ditch weird pet/side kick, and you've got The Three Investigators, Nancy Drew, and the Hardy Boys. 
Update: There's Meddling Kids I mentioned in 2019, and then there's The Mystery Business that debuted in 2024.

Wacky Races
I've written about this one before--and Richard has run it. Still needs a game, though.
Update: Still just the board game, so far as I know.