If you are looking for Rickey signed cards, try Tom Orr (Atomic Sports). He does regular private signings and usually has one or more with Rickey each year. He also lists lots of his cards on eBay. Good guy.
I don't see any Rickey autographed cards in his current auction, but here is a link to
sold/completed auctions of his. If nothing else, you can see lots of authentic autos.