If you want something for your clowns to host in, I would recommend a Toadstool leather (Sarcophyton sp.) for your clownfish. These will make perfect hosts for the clownfish, and often will resemble an Anemone. Many other types of leathers including the Devils Hand (Lobophytum sp.), Spaghetti Leather (Sinularia flexibis) and Finger Leather (Sinularia sp.) will also work fine.
Other good hosts include the Colt coral (Cladiella sp., or, Alcyonium sp.), Kenya Tree (Capnella sp.-should be added to a mature aquarium), Alveopora (Alveopora sp.), Torch Coral (Euphyllia glabrescens), Hammar Coral (Euphyllia ancora), Bubble Coral (Plerogyra sp.), Green Star Polyps (Pachyclavularia sp.), Xenia (Xenia sp.?), Frogspawn (Euphyllia sp.), etc.
There were many I never meantioned, only due to the care level required for them, and the difficulty of keeping them sucessfully alive. Some of these include the Flowerpot (Goniopora sp.), Plate Coral (Heliofungia Actiniformis), and Elegance (Catalaphyllia sp.) to name a few.
Take Care,
Graham