I'm sure all of us have one or two cards that we have traded or sold that we wish we had held onto. I have been selling cards on Ebay since 2006 or so and have been selling at shows for the past year. There is one card that sticks out in my mind as one that I really wish I had not parted with. Of course, I got a good bit of money for it (it sold for around $100 on Ebay), but that's not the point.
I hope to add Buck O'Neil's auto to my collection again (on a baseball). I would prefer to add him to my HOF collection, that is, if the Hall ever puts him in. O'Neil's omission from the Hall is definitely the subject of much debate.
Do any of you have that one card that you wish you had not traded or sold, and what would it be??