There's more than just BBGs. Small soles (flatfish) work well, too, as they hardly move at all. Also consider killifish. There are various kinds, but you'll have to see what's on sale near you; blue-eyes, Aplocheilichthys normani, work well in low salinity tanks. Also Florida flagfish, though a 10 gallon might be a little small for these territorial beasts. Other killifish are very much on a "see what's available" basis.
Lots of gobies. There seem to be a lot of Redigobius balteatus gobies about, and these are a nice change from BBGs.
Pipefish are a definite option if you have regular live food supplies (like a garden pond). Endler guppies will thrive in brackish water even though it isn't natural. Wrestling halfbeaks will thrive in a 10 gallon provided there's a decent water current for them to play in (they don't explore the tank much, but they do expect to be able to swim into a current).
Malayan snails, nerites, and glass shrimps give you some options at the invertebrate end of things, and in really saline water (50% seawater upwards) you can give blue leg hermit crabs a go, too.
Cheers, Neale