WeMod - Personalize your gaming experience Thousands of free mods and trainers for your favorite single-player PC games — all in one place.
Cheat Engine - Cheat Engine is an open source memory scanner/hex editor/debugger for Windows.
Fling Trainer - Fling Trainer gives you the opportunity to download PC Game Cheats and Mods for many games without asking for any payment in return.
GameCopyWorld - An index for Game Backup Instructions, No CD Patches, and Game Trainers
scanmem & GameConqueror - GameConqueror is a GUI for scanmem.
Gamepressure - Gamepressure allows you to stay up to date with the gaming industry by providing news and lets you beat every game easily via walkthroughs and guides for console and PC games.