ok so i was talking with a friend a few months ago when i came up with this idea, but i never get the chance to mention it, so I'm talking about it here.
so the basic idea is that its this chubby lil boy scout, maybe twelve years old, and he has no idea why hes here, but he does know that a scout should always be prepared, so in literally any situation he reaches into his backpack and pulls out exactly what the party needs (and maybe he has a dumb gimmick like "i have just the tool for the job") every time he manifests a new tool..
and the catch is that there isn't any magic involved at all, its all normal stuff, the party could be fighting a dragon, and since hes so little he doesn't register as a threat he can sneak up to it with the fire extinguisher hes had this whole time put out its mouth or something.
A more freeform game like Toon! might accommodate your character concept. D&D doesn't.