1 2 & 3 - The Lionhead trilogy. Before Microsoft made them toil away exclusively in the Fable mines, Lionhead produced Fable TLC, Black & White, and The Movies. Fable you can get on Steam, but the others have never been available digitally to the best of my knowledge.
4 & 5 - Dungeon Master 1 & 2. DM 2 The Legend of Skullkeep in particular is highly regarded by old school RPG enthusiasts.
6 - Captive. More dungeon crawling goodness, this one in a sci-fi setting.
7 - Blade Runner. This game seems to be on quite a few lists, with good reason. It's also the one we're least likely to see because the source code and assets are gone.
8 - Warhammer: Dark Omen. The sequel to Shadow of the Horned Rat which was released on GOG in 2015. Hopefully they've patched the intiial issues by now.
9 - Myth II: Soulblighter. I wouldn't mind having them all, but Myth II is the priority.
10 - Star Trek: Voyager – Elite Force. What should've been a popcorn shooter turned out to be one of the best Star Trek games out there.