Also - another variation I haven't seen discussed before is on the card of #20 Harry Greb.
He comes in 3 varieties before we even get to the gray/white backs. Light blue shirt, solid white shirt, and 1/3 light blue and 2/3 white. None of the 3 are really scarce. In combination with purple/dark gloves and white/gray backs, he may have 10 or more total possible cards. You can see all 3 shirt variants on eBay right now, as I don't have a plain white shirt, but here are the 2 I currently own (both white backs):
https://imgur.com/a/LnXAz
Unlike many of the leaf printing discrepancies and differences, this one strikes me as legitimate, proper variation that should be catalogued.