2008 Upper Deck - Multi-Product Insert Yankee Stadium Legacy #YSL6742 - Andy Pettitte
Courtesy of COMC.com
This set has 6,742 consecutively numbered cards, one for each game at the original Yankee Stadium. I think they did a major redemption for the first person to put together a complete set, since this "insert set" was inserted into multiple 2008 Upper Deck products.
http://www.beckett.com/news/arkansas...cy-collection/
2008 Upper Deck Documentary has almost 5,000 cards just for the 2008 season.