Royal Gramma Basslet
An interesting fish with lots of color is the Royal Gramma Basslet - Gramma loreto. It tends to find a spot it likes, and defends it against intruders. This fish doesn't actively swim around in the tank, except during feedings. The difference between this fish and the Purple Pseudochromis is that the colors of this fish merge or blend together, while the other fish's colors do not. Reef-safe.
Additional reading about Gramma loreto courtesy Quality Marine.