Here's what I know. I could easily be wrong.
X-women: The Sinister Virus - prototype, canceled
Lobo - finished? Could swear I've seen it before
Congo: The Lost City of ZINJI - never even heard of it, but there was a Congo game on Saturn, correct?
Garfield: The Lost Levels - Sega Channel exclusive thing I think. I have heard the game exists in cartridge form, but wasn't released.