It is true that alot of retailers come up with their own names, I think it is necessary with so many varieties and color combinations of zoanthids in particular-without the crazy names it would be really hard to keep them strait with customers.
That being said, there is a website that is trying to become the index for all named zoanthids, it is
ZOAID (I think it's okay to mention because they do not sell anything-but mods please let me know if I am wrong) This website is run by a guy named jeremy (WHODAH on the forums) along with a few others and they are very knowledgeable on the subject of zoanthids. They write very informative articles and try to keep lists of predators, diseases etc..
If you have searched the web for info on zoanthids, I think you will be suprised on how little useful information you actually find and I really appreciate other hobbyists like this who take the time to put together something like this for the rest of us.