Lemmings for nes sealed, it seems to have a bit of value. I got it during the nes days and just never played it. I should have more sealed games, but I had a tendency to open up stuff and read the manual in the car. I have games that I'm pretty sure I never actually played, just open. A few have some value, I could have sold them, but a used one, and walked away with extra cash.
I also have kirby superstar, warios woods and tin star for snes, zoop for genesis and a couple 3do, saturn, sega cd and jaguar games still sealed. When I hit ps1 my sealed collection explodes, I've already sold suikoden (120) and castlevania sotn (300) and replaced them with used ones for a fraction of the cost. Current gen gamecube is about 40% sealed, 70% ps2 and 80% of my xbox games are sealed. I got some gba and gbc games sealed, I need to sell my dragon warrior 3 and tactics ogre sealed copies and replace them with used one.