Slay the Spire style deckbuilders (
Neoverse,
Deck of Ashes, etc.) are pretty popular right now, but I guess you already know that. You can have fairly simple art on the cards and still have fun gameplay.
First person dungeon crawlers are always fun (to me), like ye olde Eye of the Beholder or
Sakura Dungeon (made with Renpy).
I've had a lot of fun with simple walking-around-maps-Fighting-Fantasy-adaptation
Deathtrap Dungeon Trilogy.
In a dream come true world, you'd make a tactics fighting game, like Final Fantasy Tactics, XCOM, perhaps more like chess such as
Into the Breach, or even a hybrid card/tactics game like
Children of Zodiarcs (just better writing). That's probably a liitle bit ambitious though.
Resource allocating dice game such as
Elder Sign: Omens?
Some kind of turn based base building game? I have no example, but turn based Sim City with nasty disasters, turn based
Frostpunk, or turn based castle defense, something like Widenyo, sorry, that's a pretty obscure game, but you can read a bit about the gameplay
here.
I also wouldn't mind seeing a straight up visual novel (maybe with stat rasing) that was more hardcore in its gameplay, with lots of dead ends (not as hardcore as Hanako's Long Live the Queen, but a little of that). Maybe some point and click adventure style gameplay in there, like you always talk about, which can be done pretty simply as first person in Renpy.
Anyway, just dropping ideas that I think are within your capabilities. Or how about a massive choice driven third person adventure game like
Detroit: Become Human?
