This is a weird project which has grown up from another game which I failed miserably to develop.

Airquake for Quake 1 is a classic 1990s

MMORPG attempt in Quake (DarkPlaces)

Berserker Quest 6: The curse of the onyx medallion is a punishingly difficult and somewhat light-hearted co-op/singleplayer dungeon crawler.

Cool rpg attempt with random map generation.

This quake mod was started by Gooseman, the man behind CouterStrike. Very nicely done. GL compatible, Navy Seals weapons compilation patch. Includes a couple of levels.