The Kardboard King is at it again -- Rob Kardashian is putting his rare Honus Wagner autograph card up for auction ... and we're told it could fetch around $50k!!!
Rob pulled the card out of a 2020 Topps Dynasty pack he purchased for $750 from the folks at the Bullpen card shop in L.A. back in November.
The guys who opened the pack for Rob went absolutely bonkers when they realized what they had ... a 1-of-1 authentic "cut signature" card from MLB legend Honus Wagner, who died in 1955.