Stars and stripes puffer, probably a porcupine for a while (they get nicely large) theres also dwarf puffers, although id stay away from some of them (they are like...evil) and uh...mabe a dogface too, that might be a good choice. There are others, like a "zebra" puffer, but i dont know how big they get, and quite frankly, im not sure how rare they are, lol