If you have flow, madtoms and darters would work. You kinda need to pick. Darters or sunfish. Depending on dimensions, Rock Bass would be good. Sunfish don't like flow. Creek Chub can tolerate anything. Hogsuckers would work, though they like a bit of salt.
So now the stock list.
You could have a madtom or 2 with a darter colony and some creek chub, though I would be cautious because they can get 12 inches.
2 Rock Bass
15 topminnows
I know nothing about hogsuckers besides that they like a bit of salt and they are like flounder.
You could do some sunfish. Depends on what food you would feed.
Gimme some context. What do you envision? What food would be available? What are the dimensions? Do you plan to have plants?