Acans are a really colorful, easy to care for, low-med light LPS
. One of my favorites.
Some Zoanthids, Palythoas, Ricordia mushrooms, or Green Star Polyps, would be some colorful soft corals.
Or if you like SPS
, there are some really cool colorations of Montipora out there. Superman, Sunset, are 2 of my favorites, but can be pricey.
Even the regular Red Monti Cap, is really colorful in a tank, and a fast grower, as far as SPS