I only used my Commodore 128 in C64-mode and only for games, except to print banners on a dot matrix printer. (Dot-matrix banners were cool back then.) I haven't found a list of games that were exclusively released for the C128. Most of what I've found are games that had an "enhanced" C128 counterpart, but also were released for the C64. Has anyone seen a list of truly exclusive C128 games?
Can't think of an example for you but here's a weird one: Shotgate and Konflikt found here: http://www.quernhorst.de/atari/sk.html Only 20 Cartridges were manufactured and I'm one of the buyers. There's a list at the bottom haha -doulomb
There's a very small list at: https://en.wikipedia.org/wiki/Category:Commodore_128_software I've never used a C128, but I've heard it was a good machine.
Thanks for sharing! Love seeing these sorts of things. The list does include four true exclusives: A Mind Forever Voyaging, Trinity, Bureaucracy, and Beyond Zork. All four are interactive fiction. Back then I wouldn't even have counted these as games. It's a start.