if i was to give the simplest of answer i'd say the fishing mini game from stardew valley, but it could be any mini game that introduces a notion of challenge & reward, no need to make the challenge hard persay, it just needs to make the player feel great when succesfully catching a fish, especially a rare one ! Even a simple click per second challenge type of thing would suffice. Still, your idea is great and if you can, you should definitely keep working on it a little bit after the jam, i would love to see its growth :)