Classic Doom.Com A pretty damn good resource for walkthroughs and all text things
Doomworld.com Home of the largest forum system for classic doom in existance, with many new projects weekly, as well as the official Cacowards and nominees posts
Wad-Archive A vast archive of over 50,000 .wad and .pk3 files for old school doom, including all the 90's cd-roms. Much like Doomworld, heretic, hexen, and all the other source clones are covered
Realm 667 Even though the front page focuses on the best new projects to hit the community, it is also home to the repository of resources for editing doom mods, including a massive bestiary
ZDoom.org Wiki A great resource for all things related to the Zdoom source port, editing ACS Scripting, Lumps, and of course zdoom.org is where you get the source port. The Zdoom source port is now available for the Raspberry Pi!
WadsInProgress Good spot to find wads/mods that aren't even released yet, and form a cult following of a fanbase for their authors
ID Software's Website Here is the home of the Dallas and Frankfort giants, ID SOFTWARE! Creators of the Wolfenstein, Doom and Quake series
DOOM.COM The official website for the latest doom reboot in 2016! DOOM Finally has its own devoted real website after all these years!
Wolfenstein II at Bethesda id Software's legacy edition of this game was in 1992. It's had very many sequels, including this upcoming one!
And speaking of DOOM and WOLFENSTEIN, What about some QUAKE CHAMPIONS??
Commander Keen Fansite A whole website dedicated to Keen with fanmade sequels
Mini-Doom An indie game project page, with the dev page of Mini-Doom II
DOOM Archive.com A vast archive of thousands of doom wads of all types.
DOOMGEON! a hack and slack dungeon crawler on itch.io, under development for Android devices.
Doomshack/Oldsites Nearly 200 archived sites from the 1990's and 2000's that are classic doom-related
doomshack.org\\recent The most recent 20 wad file uploads to doomshack.org
www.doomshack.org and of course the main site of doomshack.org, ran by doomkid and Mr Crispy.
The Sentinel's Playground is now a free, automated server host for Zandronum.
Chaosunleashed.net is a massive directory listing server full of mods and level packs
Devilhunter.rfc1337.net is another of the same, with Zandronum and Skull tag stuff, wolfenstein, and more
GZDOOM, ZDOOM, and QZDOOM my favorite source ports for doom. I currently am always using GZDoom since ZDoom is defunct
Zandronum is a multiplayer source port for doom.
Brutal Doom is a super hardcore gory crazy mod of doom that also works with other level wads. Music by badass Andrew Hulshult
Project Brutality This is the highest quality expansion of content for Brutal Doom v20b that capitalizes on breaking new ground in terms of gameplay, features, weapons, enemies, balance, visuals, sound, and so much more
Cacowards Every year these happen at doomworld.com for mappers and other such creators of wads and megawads
Realm667 starts with sort of an editorial of the best of the best in new mods, plus offers extended bestiary and weapons, as well as other things
Brutal Doom 64 is a BRUTAL remake of the original Nintendo 64's version of DOOM that had new everything including enemy sprites. Now it's even better
Doomer Boards General, Projects, Off-Topic, Music, Console & PC Games, Anime, and Mapping Workshop are the boards.
Doom WAD Reviews a place for just some guy to post my opinions on WADs he has played starting some time in 2010
Doom 64 Retribution Doom 64 EX and Doom 64 Absolution are all three attempted recreations of the original Nintendo 64 classic. I'm told to get N64EX to be the closest.
Quake Soundtrack Now On Vinyl Trent Reznor's masterpiece of a soundtrack for id software's Quake is now available on Vinyl!
Sonic Robo Blast 2 is a 3D open source Sonic the Hedgehog fangame built using a modified version of the Doom Legacy port of doom
Ancient Aliens my fiance and my favorite modern mod for Doom II -- @doomwadstation.net
Doom Wad Station.Net DWS Forums, Doom 4 3 2 and 1, Quake and Wolfenstein 3D
Golden Eye for Doom 2 A total conversion for Doom II of 007: Golden Eye 64
Zorasoft.net/doom.html A wad section of someone's site that requires GZDoom 3.0 or above
Hacx 2.0 is a main iwad for doom2 source ports that is also it's own free game
Harmony by Rabotik is an independant game inspired by 3D shooters from the nineties. Works on GZDoom as an iwad
Prodigal GZDoom Wads are made by a random amateur game designer, musician, writer, and 3D artist.
http://icequake.neocities.org/valvedev/tools.html A Neocities-Native site with a huge list of Quake-related Editing Tools.