Satanists have perverted it, but the christians once used it, too. The five wounds of christ. An ankh would work too, since the ankh represents the cycle of birth, death and rebirth, plus eternity.
I've seen them but I think only the people who pre-ordered XCM champions got a deck and a chance to purchase an extra one... But I dont think there is any word on when they would be available to the public if they ever are....