Chats and Forums
EN World Forums, The Pits of Evil, Yahoo! Clubs: d20 Gamers, Yahoo! Clubs: Dragon Lords of Melniboné, Yahoo! Clubs: Star Trek for the d20 System
Dragonstar
Arcanum of the Stars, Brutorz Bill's Dragonstar Page, Chrysalis - Campaign to the Stars, Darkstar, Exodus, Fantasy Flight Games - Dragonstar, Mike's Dragonstar Page, Neo's Datalink, Starfarer's Netbook, Yahoo! Groups: Dragonstar
Publishers
0one Roleplaying Games, Alderac Entertainment Group - d20, Alea Publishing Group, Anubium, Archangel Studios, LLC, Atlas Games, Bad Axe Games, Bastion Press, Black Queue Games, Bottled Imp Games
Spycraft
Alderac Entertainment Group -- Shadowforce Archer, Alderac Entertainment Group -- Spycraft, Dark Inheritance, Defense Research Agency, Dropbox #7, Hyperkinetic, Modus Operandi, Odin's Spear, Yahoo! Groups : Living Spycraft: Canada
Ancient Worlds: Multicosm
Includes ancient Rome and Iceland campaign settings, new clases, feats, solo adventures, monsters, new rules, and product reviews.
Chilling Tales Horror Roleplaying
A collection of resources and gaming materials for horror roleplaying in any campaign setting using the d20 System
Creation's Edge
Creation's Edge is an on-line resource for D20 fantasy RPG settings. Offers a free section of monsters and magical items.
creaturedb - the RPG monster database
Open, free, online database for rpg monsters, creatures and npcs. Accepts (and encourages) submissions for home brewed monsters / beasties. Authors/copyright holders receive full credit/ownership/copyright for their work.
D20 Fortress.com
A large source of D20 material. Has maps, downloads, and other useful items for the D20 game.
d20 Magazine Rack
A site that has free downloadable electronic magazines such as d20Zine and TempesT's Lore, product reviews, gamer resources, and gaming contests.
d20 Modern Roleplaying Game
The official site for The Wizards of The Coast d20 Modern RPG. Features free articles, downloads and artwork for the game.
d20 Tools
Contains tools for the d20 system such as new equipment, feats, skills, classes, and characters.
Dark Matter d20 Conversion
A site for a d20 System Conversion of the Dark*Matter conspiracy & espionage setting. This includes conversion of Feats, Skills, Classes, and Magic/FX abilities as well as creatures and aliens.
DireKobold.com -- A D20 Adventure E-Zine
An internet D20 adventure magazine dedicated to the three principles of quality, quantity and flexibility.
EN World
Latest news and reviews, forums, a conversion library, and very popular forums. The quickest D20 news source with inside information on many upcoming products.
Free Gaming Association
The FGA is a non-profit organization dedicated to promoting open gaming and supporting open gaming publishers.
Malls and Morons
A humor D20 game that takes place in the deadliest of places, the local mall.
Modernized! - D20 Modern Ezine
A free ezine, published to the web, that provides new material, suggestions, and other useful bits for a D20 modern campaign.
Open Gaming Foundation
Contains Open Gaming Licenses and a clearinghouse for information about the system.
Palaestra: A Land of Magic and Intrigue
Maps, fictional stories, artwork, house rules, campaigns, and general game information
PCGen
A character generator and maintenance program aimed at supporting any and all d20 roleplaying games.
Resident Evil D20
A D20 website which converts the Resident Evil video game to the D20 system rules.
Roleplaying World
Contains reviews, articles, and background information including places, people, races, and religion for a new campaign world in a Roman Empire setting.
RolePlayingMaster
A software utility suite for D20/D&D, incorporating character/NPC/monster generation, adventure building, and in-game combat/BattleMap manager.
RPG United: d20 System
Lists and descriptions of products available for d20.
RPG Vault
Features new races, feats, and classes for the DC and Everquest universes.
Ruby Covenant Roleplaying
Australian based web site that offers D&D & d20 roleplaying information and products to RPG fans.
Ryan Dancey: the D20 System and the Open Gaming Mo
Discusses the proposed open-sourcing of Wizards of the Coast's gaming system.
Salon Technology: Dungeons & Dragons to go ope
An interview with a gaming executive about an open gaming license for role-playing games.
Salon Technology: Opening the Dungeon
Article about gamer reaction to Ryan Dancey's open gaming proposals.
Shadowrun D20 Conversion Site
A conversion site for the Shadowrun system by Wizkids to the D20 Format.
Slashdot: Where Daemons and Dragons Collide
Feature story of the Open Gaming Project with reader feedback.
Starcon Continuum Homepage
New rules for a futuristic D20 campaign. Has information on starships, new skills, weapons, along with bios of characters in the world.
SVGames - Global Game Source
Offering d20 games and accessories worldwide. Cheap shipping and thousands of items. Managed by an award-winning team.
The Boneyard
d20 conversions of creatures and rules from Advanced Dungeons and Dragons and Alternity.
The d20 System
Official site of the game engine and the Open Gaming License.
The Game Hub Character Database and GM Tools
Contains characters and encounter levels, offers ability to create and store characters online.
The Gundam D20 Homepage
This is the homepage of the free D20 role playing game system conversion for Mobile Suit Gundam.
The Hypertext d20 SRD
Contains the version 3.5 d20 system reference document and is indexed, hyperlinked, and searchable.
The Open Gaming Exchange
News and directory of open gaming sites and products.
Twin Rose Software
Contains the demo and update downloads of the Campaign Suite program for generating characters, maps, and campaigns.
Weird War II - The Complimentary Website
Has variant rules, new equipment and vehicles and information for the PEGInc game Weird War II: Blood on the Rhine (and expansions).