A 10-gallon fish tank presents a wide range of possibilities for stocking pretty, vibrant fish. If you are looking for fish that would have a role in keeping the tank in good shape, you can stock Cory Catfish, Neon Tetra, Dwarf Gourami, Fancy Guppy, or Betta Fish.
I have one Aqua Culture 10 Gallon Empty Aquarium and put some guppies, a few bettas, and two cory fish. They are pretty cool and keep my tank in good shape.