DOOM 64: Unseen Evil Ultra Nightmare

Black Mesa: Classic is an ambitious fan project aimed at porting the Black Mesa remake (on the Source engine) back to the original GoldSrc engine from Half-Life. The mod restores the atmosphere of the original game while adding a number of improvements and maintaining low system requirements.

Opposing Force: Enlightened - a mod for Half-Life: Opposing Force that adds a lot of new weapons, improves lighting, effects, and atmosphere of the original campaign, making it visually more modern without changing the storyline.

C&C: Revolt GLA — a mod for Yuri's Revenge that brings together five iconic factions: the Allies, the Soviet Union, Yuri, GLA, and the Empire of the Rising Sun. For the first time, they can all clash on the same battlefield to determine the strongest. Unique units, technologies, and distinctive gameplay await you for each faction.

A major mod that significantly improves the original FlatOut. It reworks the career mode and car physics, adds a new soundtrack (including tracks from FlatOut 2 and Ultimate Carnage), new modes from Ultimate Carnage, as well as cars and tracks from FlatOut 2 and Retro Demo, 4-player split-screen, working multiplayer and much more.

Half-Life: Recovery is a fan-made sequel to Half-Life: Decay. The main protagonist is Colette Green (Gina Cross's partner), and she, together with Dr. Keller, needs to obtain a portable teleportation device to escape Black Mesa — their survival depends on it.