“Nixon was planned to be part of 1996 Leaf Signature Series Baseball, a turning-point product for baseball cards in that it was the first MLB set to have an autograph in every pack.
The cards were made and sent to Nixon to sign. But, for whatever reason, they never made it back to the Donruss/Leaf. There are rumors out there as to what happened to the cards, but nobody knows for certain. Without the cards, Nixon was dropped from the checklist.
It wasn’t until several years later that they surfaced. In 2005, copies of the card started appearing on the secondary market.
According to Freedom Cardboard, the cards were discovered inside a forgotten Atlanta storage unit Nixon used. The cards were in the bottom of a suitcase.” – Beckett.com