Thread 3.1
Source ports ZDoom (G)ZDoom downloads DOOM2.wad or DOOM.wad is required to use (G)ZDoom. ZDoom v2.8.1 is the barebones source port. Non-openGL.
GZDoom is an OpenGL version of ZDoom that provides a lot more options. It even adds bloom for brightmaps too.
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Get started with GZDoom (Video) PrBoom PrBoom homepage If you want the most vanilla experience but with some tiny features, get PrBoom. It can run nuts.wad.
Zandronum Zandronum.com Zandronum is multiplayer doom. Just like GZDoom you can use it as a source port for singleplayer too.
Editing tools★
GZDoomBuilder-Bugfix GZDoomBuilder-Bugfix Doom builder 2, but x10 better. Voxel, 3D model, dynamic lights, and 3D floor support.
Slade 3 (3.1.5 as of now) slade.mancubus.net Slade 3 is probably one of the best editors I know when it comes to non-mapping in doom modding.
Note: to compile ACS in Slade 3, you need to go to ZDoom.org and download ACC to compile your ACS text files into a .acs format. And yes, there are ACS de-compilers on there too.
This thread mainly covers classic doom games, but you may talk about the new Doom games aswell.
May or may not edit some things to this later