You can get loads. I've used bloodworm, white mosquito larvae (they didn't like that so much as the bloodworm) beefheart (again didn't like it too much, plus it makes your water messy!) dapnia (liked it, but went more crazy for bloodworm!) and cockles, but these are only for larger fish.
I would suggest you try a variety and see what your fish like best. I would wager on the bloodworm though, but I may be wrong!!!