Well for types of corals there are:
Soft Corals (what you have, plus leathers, Xenia etc.)
LPS (Large Polyp Stonies, Trachyphyllia, Hammers, Duncans, Brains etc.)
SPS (Small Polyp Stonies, Acropora, Montipora etc.)
Easy corals that are very nice are leather corals, however, if you get a leather coral you can't keep LPS with them. Leathers secrete a substance toxic to LPS corals. Alternatively you could get some LPS. I have 3 Trachys (Lobed Brain Corals) in my tank ATM. They are fantastic. Easy to keep. Feed them every now and then at night (this is when they're feeding tentacles extend) and they're happy. At the moment you could get just about any coral.
What kind of lights of you have?