I have a few sealed "retro" games. I've found them all in the wild. Why there was a sealed copy of The Jungle Book at a yard sale, I'll never know. I think it's cool that they never got opened. I'm not a sealed collector though. I don't seek them out.
Then, there are all the 360, PS3, Wii, and WiiU games that I never got around to playing. I found most of them cheap and bought them on a whim. I just don't play as many games as I'd like to.