Looking for interesting cacti to add to my wishlist!

[CactusBrett]

I'm always looking for new cacti names to add to my want list! I'm particularly interested in unique cacti such as the single species genera. I want to find something a little different from your typical mammillaria or opuntia. I have the leuchtenbergia and the obregonia and for a while i was obsessed with collecting all the astrophytums. Finally got the caput-madusae. Does anybody know any unique or out of the ordinary cacti they want to share about?

[jmoney]

Have you considered mostrose/cristation? Those forms are unusual.