Blue neon goby? Peacock goby? Purple pencilfish? Coral red pencilfish? Celestial pearl danio? Forktail blue-eye? Red-stripe killifish?
Just depends on what kind of tank you want to have, how hard you are willing to look for your fish, and how much you are willing to spend. Because, although black and white, you would be hard pressed to find a nicer fish than a zebra plec.