sorry I don't have any to offer.. but I have had one in the past.. I beleive it was not a snail but a cowrie.. I think it was beige with brown spots.. I also beleive it was a hitchiker on some TBS LR..
One I had in the past were typical looking snails with a checker board like pattern on it. Lots of different types of inverts eat zoanthids. Hopefully it won't be hard to get something.