Quake Series

Deathmatch Zone, The - http://www.denken.com/dzone/
Includes news, downloads, reviews and player guides for Quake I, II and III.

Quake 24/7 - http://www.quake247.com/
Contains screenshots, cheats and an overview for the series.

Quake Console Commands - http://www.ccs.neu.edu/home/danielr/quake/
Documentation on how to use the Quake console.

Quake World - http://www.quakecas.freeservers.com
Includes downloads, screenshots and animated gifs.

QuakeFinger - http://finger.planetquake.com/
Game developer .plan files.

QuakeWorld.Net - http://www.quakeworld.net/
Includes game information and news.

The Gamer's Guide - http://www.bluesnews.com/guide/
Includes a series guide and a game glossary.