Some flasher wrasses would be ok in that size tank - McCosker's and Carpenter's are the two that are most often recommended. Depending on what corals you keep, some dwarf angels (Coral Beauty, Cherub) could work in your size of tank. A royal gramma would be a great option for a colorful, peaceful fish that works well in a smaller tank. A pink-streaked wrasse would also be great if you can find one - they look similar to a six-line, but with a more peaceful personality and less likely to become the tyrant of the tank.
If you can handle the price, either a Helfrichi firefish or a Starck's Damsel would be really nice for your tank. Both sit around $120-$180 most of the time.
Depending on how long your tank has been up, a smaller dragonet (like a Ruby Red or Red Scooter) would be a nice addition, but both would need a thriving pod population, and even with that they might be pushing it for a 2' tank. Dragonets are kind of weird in their requirements - if your tank can support them they're the easiest fish ever, and if it can't then they'll break your heart. With an externally grown pod population it might be possible to keep a mandarin in your tank, but not really something I'd risk.