Royal gramma, Stigmatura tailspot blenny, pink-streak or possum wrasses, zebra-bar, scissortail or blue-gudgeon dartfish, firefish, literally dozens of species of gobies ... all are possibilities, but don't try to throw _all_ of 'em in there!
The first thing to decide, for me, is which fish do I really want to look at for the next five, ten or more years - then, will it fit in my tank, with my community.
~Bruce