Yasha Goby with Red Banded Pistol shrimp, best combo ever. Engineer gobies are fun to watch, but they'll drive you crazy with all the digging, just like yellowhead jawfish. Midas Blenny, Lawnmower Blenny and just about any blennies are fun to watch as they pounce from rock to rock, they also take bites of algae off rocks. If you are extremely lucky, you can get different types of firefish gobies to school together which I successfully did once with red firefish, purple firefish and helfrich firefish (would not recommend the gamble though). Blue Star Leopard wrasse are nice, they bury themselves in sand for couple of days until they get comfortable (but need some reef experience). If you like to see schools of fish, dispar anthias are nice. If you had to choose another anthias and that doesn't school like other anthias' do, maybe a Sunburst Anthias.