Classic Doom.Com A pretty damn good resource for walkthroughs and all text things 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 Wiki A great resource for all things related to the Zdoom source port, editing ACS Scripting, Lumps, and of course 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 A vast archive of thousands of doom wads of all types.