I think a reasonable "next pick" could be someone from Spongebob. Personally, I'd like to see Squidward (it'd be cool to see him using his clarinet as a projectile, plus he could be quite a fun lanky grappler, a rarely-seen archetype, due to his biology as a squid/octopus) or Plankton (he'd be really cool as a sort of "tinkerer" archetype, using various machines and the like to fight opponents similar to someone like Zim.) Even so, I think Mr. Krabs would be cool as well, though!
Some more unusual characters a friend of mine suggested are:
- Larry the Lobster, who'd be like a sort of bruiser heavyweight archetype with a couple of grapple moves
- Hans the Hand, who would be like a boss similar to Master Hand but the joke is that it's literally just the Spongebob hand
- Mrs. Puff, who'd be a bizarre mix between "driving instructor" and "master criminal" as well as having a unique "Puff Up!" mechanic
I think there's a lot of potential concepts here! I feel Squidward is the most likely of the bunch, but Spongebob alone has a lot of potential picks - and that's not even getting into some others!