There are lots of good fish for a 10 gallon tank, particularly among the gobies. You could also keep wrestling halfbeaks, dwarf mosquitofish, pipefish, flatfish, and a variety of other small, relatively inactive species. For flatfish a sandy bottom tank is best, while pipefish prefer something with ornaments or plants to hide among.
But I'd recommend gobies with shrimps and Nerite snails, maybe with a few Endler guppies if you wanted, and then decorate the tank with rocks and shells to make something like a rockpool. At a higher SG, you could keep shrimps, Nerites, and even certain kinds of anemone (beadlet anemones) together with some brackish/saltwater gobies or blennies.
So, lots of possibilities.
Cheers, Neale