Wolf Skevos-Jones! Essential.
Coming of the Storm
Weapons of Vengeance (I know it was only a demo but its influence was massive)
WSJ is the reason my eyes were opened to the world of modding Wolf3D way back in 2002 and while my appreciation for the classic game as-is has gone up in recent years it was the technical innovation and features of WSJ's sets that made me go 'wow, you can do this in Wolf3D?'.
Project: Weltuntergang by Kuki comes to mind.
He asked for the mod to be withdrawn (which is a shame, yes).
Really? I believe I grabbed that three years ago when I went on a massive Wolf map/mod hunt.