In a 10gal, you could do a pair of knight gobies I might imagine, bumble bee gobies, wasp gobies, half beaks, mollies - even guppies can tolerate a little salt in their water.
Indian mudskippers also, as well as little things like red claw crabs or fiddlers, even small rainbow fish like celebese rainbows.
Not all together of course, but thats a decent list of what you could keep.