The FF games are going for quite a bit sometimes on ebay, also: Man Enough, Afterlife, Alter Ego, Lula The Empire cums back, the Spellcasting series (any Legend title really), the Star Saga series, Tsunami games, Panik in the Park, and Atari Action Packs perhaps?
and of course, this, super rare and expensive:
these are getting kinda rare now: