PrBOOM - Enhanced DOOM source port. Was ported by Bero, then neglected and never polished off, nor was pWAD support ever added in. I realize we have nxDOOM, but it has saving issues on levels that are too large, or have to many living enemies on them during save time. Also nxDOOM carries over the bugs and restrictions of classic DOOM which BOOM (the source port prboom is based on) resolved. On top of that PrBOOM brings many new features to the tables that classic DOOM was not capable of such as MBF support, conveyor belts, wind effects, ice effects, basic BEX support, etc.
Exult: Executable for Ultima VII. Perhaps one of the best RPG's ever created!!! Came in two parts.
Duke Nukem 3D
Shadow Warrior
Descent
Cave Story
ReMood: Doom source port based on old DOOM Legacy. This should be portable because Sonic Robo Blast 2 was ported which is also based upon the same DOOM Legacy source code.
I would provide links, but all games are easy to find via Google.