3D Map Realm
   Reviews of Quake 2, Half-Life and Unreal single player maps. Also provides testing services and a discussion forum.
   http://3dmr.gamedesign.net/

Cooltech Games
   Patches and modifications for Half-Life, Unreal Tournament, and Quake.
   http://cooltech.rocketage.org/ctgames.htm

Crosshair Central
   Provides crosshairs for Central, Quake 2, Half-Life, Counter-Strike, Sin, and Kingpin, tools, and tutorials.
   http://www.planethalflife.com/cc

DAV Levels
   Levels and maps for Doom2, Heretic, Hexen, Half-Life, Quake and Quake2.
   http://www.planetquake.com/davlevels/

Foyleman
   Soldier of Fortune, Serious Sam, and Return to Castle Wolfenstein.
   http://www.modsonline.com/

Gamelaunch 3D
   Front-end for configuring 3D games. Contains news, downloads, and support.
   http://www.gamelaunch3d.com/

Garjen Software
   Add-ons, custom levels and utilities for games such as Duke Nukem 3D, Wolfenstein, and Lemmings.
   http://www.garjen.co.uk/

Grey Fusion
   Tips and ideas for editing game engines for Half-Life, the Quake Series, Red Faction, and the Unreal Series.
   http://www.greyfusion.net

M Planet
   Includes mapping and level editing instructions, and downloads.
   http://www.geocities.com/manneonline/

Mirage's Maps
   Maps for Half-Life and Quake 3.
   http://xennon101.tripod.com/miragesmaps/

Mod Pages Network
   Modification downloads and reviews for games including Half-Life, Unreal Tournament, Quake II and III, Rainbow Six, and Rogue Spear.
   http://www.modpages.com/

Poly Count
   Includes downloads, modifications and game resources.
   http://www.polycount.com/

Slacker's House
   Unreal Tournament, Unreal Tournament 2003, and Quake 3 maps.
   http://slackerz.8m.com

Super Capture the Flag
   Includes game modifications, downloads and information. Plays on Quake and Half-Life.
   http://www.sctf.net/

The Bullseye Crosshair Collection
   Includes modifications for the Quake Series and Half-Life.
   http://www.bullseyecrosshairs.com/

The Open Source Development Team
   Contains maps for Counter Strike and Unreal Tournament 2003.
   http://www22.brinkster.com/osdt/

Total Conversions.com
   Deals with modifications to games developed by 3DRealms.
   http://www.TotalConversions.com

Ultimate Mapping
   Maps for Counter Strike and Battlefield 1942.
   http://www.angelfire.com/pro/nemo/

VR21
   Offers modifications and add-ons for several games, including Doom and Quake.
   http://www.vr21.com/

Vondur's War Supply
   Includes custom maps for Quake, Quake2, Quake 3 Arena and Half-Life.
   http://www.planetquake.com/vondur

boodizm.net
   Mods, maps, scripts, tutorials and utilities for Soldier of Fortune 2 and Quake 3 Arena.
   http://boodizm.net