From the FAQ: https://www.tcdb.com/FAQ.cfm?ITEM=WrongBacks
Do you list cards with wrong backs?
Cards are printed in big sheets. First a stack is loaded in and one side is printed. Then the stack is reloaded and the other side is printed. If the process is off and the stacks are mis-loaded, then you end up with a card with the front of one card, but the back of an entirely different card. There are also cases where the printing of the back is missed completely resulting in a card with a blank back.
Since this is due to a misfire during the printing process and not a failure of the proofing/editing process, we do not attempt to catalog these sorts of cards on this site due to their random nature.
Members do have the option of cataloging these types of errors in their personal collections.
Wrong-back cards are usually considered "damaged goods" by collectors, but there is a subset of collectors who do seek out these types of oddities.
They are usually not worth any more than the normal version of the card, but may see nominal increase in value depending on the subject of the card or the team and collector interest in that particular subject/player or team.
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).