there's a bunch, but i narrowed it down to my top 5, all baseball cards:
5: Joe DiMaggio/Charlie Keller 1941 Double Play
4: 1995 Andruw Jones Bowman's Best refractor rookie (one of the most iconic baseball cards of the 1990s)
3: 1998 Griffey Jr. Bowman Chrome International Refractor (wanted this card since i was a little kid)
2: 1997 Pinnacle Certified Mirror Gold Griffey Jr. (at one point, this card was valued at $2,500

)
1: 1910 Caramel E93 Eddie Plank