New cr's is 99% random choice.
It could be anything, globumm to kalindra, to heitachi to hula.
No one knows. No one ever will.
Im guessing the bigger the collection, better the chance then
It could also be an already existing Cr as well, if that were to happen, then that Cr Cr would stopped being given out from Tourney, ELO, etc and only those already existing copies will exist. It's like a Collector's Collector