I just noticed that the 3d Realms download site isn't listed. Why? because they usually end up releasing the full versions of their discontinued games. This stuff, usually, is listed on liberated games; but it wouldn't be a bad idea to link to it anyway, since Rockstar is up there.
Currently discontinued freeware releases include: Bio Menace, Alien Carnage/Halloween Harry, Adventure Fun-Pack, Beyond the Titanic, Boppin' (via link), Caves of Thor, Major Stryker, Puzzle Fun-Pak, Stargunner, Supernova, Trivia Whiz, Wolf3D Super Upgrades addon, Word Whiz, and Xenophage: Alien Bloodsport.
EDIT: Your freespacezone.net link is dead.