Id Tech 1

For Id Tech 1 games (doom engine) my server runs Zandronum. Go grab 3.0 at https://zandronum.com/. It comes bundled with Doomseeker, which is for searching for/connecting to games. Throw all your IWAD files from your Doom engine games into the base Zandronum folder if you're like me, or if you're a sensible person you can put them in a cleaner location and point Doomseeker to them. It should try to download pwads/pk3 (maps and mods) automatically.
I'm running:
Doom
Doom 2
TNT
Plutonia
Chex Quest 3
Heretic
Hexen
Hacx