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 go.