If it weren't for a garage sale my parents had when I went away to college, I'd have everyone stumped. I had a bunch of old Apple ][+ games like Star Blazer, Miner 2049, and Mummy's Curse - all in original ziplock baggies with original instructions. I wish to hell they hadn't done that.
I have pretty much all the domestic console stuff being mentioned from Saturn, PS1 and PS2.
I'll throw out a couple but I'm sure somebody else has them:
Dreamcast imports - Headhunter (Euro. version), Under Defeat, Border Down
Gamecube import - Mr. Driller Drill Land