You have way too many possibilities to list. I will give you a few, but I think that your best bet is just to make a trip to your lfs and see what they have and what you like and write down names so you can do some research.
Small rainbows, most commonly available tetras, platies, cories, rams, otos, dwarf or honey gourami, smaller barbs are a few options. There are quite a few very cool tetras like the penguin, Pristella, diamond tetras, and ember tetras to name a few. You could also consider some smaller tankmates like celestial pearl danios. Again though, I would look into what is around you.
