Zoanthids and Palythoas are easy to keep and come in a wide variety of colors. They can be kept under lower light and are the first coral for many aquarists. Any colony of Zoas will surely be an eye catcher in your aquarium.
Leathers or soft corals are some of the easiest corals to keep. They do not require much in terms of lighting and they grow fast. They will grow tall and sway in the flow with good polyp extension when happy. Most are brown in color, but some are vibrantly colored in either the polyps or their skin. In the wild they grow in nutrient rich waters that they filter feed. Therefore, they do not require such intense lighting. The turbid water they originate from blocks the light from penetrating to their habitat which makes them rely on filter feeding more than photosynthesis.
Soft corals are some of the easiest corals to keep.