Welcome, Glad You Are Here. Like Nikki said Bi-color Bennies are super cool. Yellow headed Jawfish work well in small tanks with sand substrate. Swalisi basslets work well. Magnificent Firefish or purple firefish do well if the tank is covered. Possibly a pistol shrimp, yellow watchman goby combo. If your rock is on the bottom and then you added sand. Fairy wrasse are very cool if your tank is covered. Don't over look the small damsels if they are added all at once, in my experence, the yellow tail blue damsel is not so insane (using Charles Mansion as a reference point) in a small group. How about a pygmy angel? I hope that helps you. Steve