If you want to keep natives, there are plenty that will do well in a 10 gallon. Missouri has lots of small, pretty darters, minnows, and killifish. You could also keep pygmy sunfish (not true sunfish) which are no bigger than neon tetras but have sunfish looks and attitude. Other native options are Enneacanthus sunfish (not native to MO, but several online vendors sell them), sticklebacks (mean little things, you'd have to keep them alone), crayfish, or shrimp.
If you upgraded to a 30 gallon you could keep mid-sized sunfish such as dollars or orangespots.