I think the easiest to care for are the serpent stars. Others are reef safe, but are hard to keep long term I think. The common serpent stars are dull colors, but there are some that are red, black adn white ect.
Brittle Stars are also reef safe but will probably catch and eat sleeping/dying fish.
Sand-sifting stars are reef safe, not sure if you'd consider them colorful since they are a dullish tan. but they are amazing to watch.