So, so many.
These ones have less that 1000 votes :
Outlaws, western FPS with a Far Cry-like freedom of shoot'em-in-the-back approach, awesome cartoonish graphics, and a strong Leone vibe.
Crimson Skies, some sort of steampunk flight simulator with biplanes and dirigibles and if I haven't played it yet it's your fault.
Star Wars Rebellion, still a trillion times better than Force Commander, Empire at War, and whatnot.
Starship Titanic, a Douglas Adams adventure game, by Douglas Adams.
Trespasser, a cult game that is considered to be the best game ever and the worst. Both are probably true.
The colonel's bequest and
its sequel, Laura Bow and the Dagger of Sammun-Mak or Whatever. Sierra-on-line at its best and creepiest.
Manhunter New York and
its sequel, Sierra-on-line at its even best and even creepiest.
Shadow of the Comet was the only decent Lovecraft game before Dark Corners.
Bloodnet, cyber-vampirism RPG.
Operation Genesis, Jurassic Park (mis)management.
The 3rd Elite game, unreleased on the amiga and I wept.
These ones have less than 100 votes !!
Covert Action, awesome spy simulation. With actual spy stuff, so gimme a break with your alpha protocol.
Sea Dogs, because how many (gorgeous) pirate simulators does GOG have yet ?
Subwar 2050, even made a thread about it.
and [url=http://www.gog.com/en/wishlist/games/f19_stealth_fighter]F19, stealth flight simulators.
Nosferatu, possibly the most terrifying FPS ever. Don't make me laugh, undying !
War of the Worlds. Real time strategy, the musical.
Transarctica, ice apocalypse, giant war trains, mining mammoths. Because nothing makes more sense than sending your mammoths to work in your mines.
and [url=http://www.gog.com/en/wishlist/games/roadwar_2000]Roadwar 2000. Ultima IV meets Mad Max.
Martian Gothic, horror survival on mars.
Sheep Dog'n wolf, a Chuck Jones simulator (actually a Ralph Wolf simulator : use ACME devices to try to outwit Sam Sheepdog, and fail).
Seven Cities of Gold, because Sid Meier's Colonization and not that !?
These ones have LESS THAN TEN VOTES :
Hammer ad Sickle, unforgiving spy-ish turn-based squad tactical game. Completely unfair plot wise (too much freedom to make invisible mistakes, by starting the wrong mission at the wrong time), but awesome in terms of X-Com/Jagged Alliance action.
Death to Spies, the sequel is out for a long time now. And this smersh simulator owns any Hitman, Assassin's Creed or Sniper Elite you can throw at me.
Seriously, guys.