A yellow coris wrasse if you have sand as they sleep in it. Active and good pest eater.
Pygmy or flameback angel. Stay smaller but add last due to aggression. May pick at some corals but generally ok.
Tailspot blenny, lots of personality and picks at algae. Hangs out on rocks.
Pistol shrimp and shrimp goby or jawfish (need a lid) - interesting behaviors and will utilize bottom half of the tank.
Neon goby - active, bold, will sit on your hand
Royal gramma, beautiful colors, nice purple splash
Yellow clown goby - picks at SPS but fine with other corals. Cute and will sit on your leather corals all cozy.
This list of fish hangs out in different areas and serves different roles. Different body shapes. This limits aggression. They should get along well while adding a lot of activity.
Some of the fish are small (which helps keep bioload reasonable) but they are not shy fish and have fun personalities.