Gobies, I think one veriety of clown would be fine in this... cant think which off the top of my head ocelleris probs, blennies, dartfish, one or 2 verieties of cardinals, a Swales Swissguard Basslet would be ok... umm... dottybacks, dragonets, hawkfish, that covers all I can think of.
Yes kinda contradictory to what I said earlier, but that was more about quantiy/space, as the next tank I'm setting up is going to be huge/have rediculus veriety so anything under 100gal is sadly limited in my books lol. Though my tanks are also reefs, so there is huge amounts of space taken up by corals as well so bigger is nessecity for swim room.