TNT: Evilution (TNT.WAD)

As you likely know, TNT's Evilution began its existence as a freeware megaWAD developed by Team TNT, who had its origins in a certain Doom mailing list. A bunch of people poured their hearts and souls into the mapset, and just as it was supposed to be released, John Romero popped in, asking if id could buy it, to be published as a commercial work. TNT agreed; thus began a rigorous playtesting / polishing session that delayed the release of Evilution until after TNT put out their freeware sequel, the illustrious Icarus: Alien Vanguard. Nowadays you can find Evilution as part of the Final Doom package alongside The Plutonia Experiment (which is kind of a TNT project, in that the Casalis were members of Team TNT).

Doom II Map 14 Homage (TWM01.WAD)

DOOM II MAP 14 HOMAGE
by Tom Mustaine

Tom Mustaine submitted four maps to id’s Master Levels for Doom II. id released three of them in one form or another, while the fourth languished in obscurity for quite some time. Mustaine eventually saw fit to release it on his blog as a historical footnote. TWM01.WAD wasn’t necessarily rejected for being a subpar map; rather, it was rejected for being essentially a rewrite of "The Inmost Dens", after which McGee told Mustaine to "go make some of [his] own geometry!"

ParadoX (PARADOX.WAD)

PARADOX
by Tom Mustaine

Memento Mori (MM.WAD)

Memento Mori has the distinction of being one of the first megaWADs released for Doom II, period, seeing its first publication back in 1995. It's also one of the first community megaWADs, at one time racing neck and neck with H2H-Xmas and TNT: Evilution, at least until id bought up the latter for their own nefarious schemes. Memento Mori has its origins with The Innocent Crew - Thomas and Denis Moeller - authors of two episodes for OG Doom and the partial conversion, Obituary. From what I can tell, they helped form the Memento Mori Crew, gathering up 19 other authors, and pushed their megaWAD out in a little more than five months.

Perdition's Gate (PERDGATE.WAD)

Perdition's Gate was one of a suite of Doom commercial WADs published by WizardWorks. The project started out between Tom Mustaine and his father, Bob, as a third megaWAD for inclusion with Final Doom, but at some point "the Final Doom window of opportunity had closed", so they took the project over to Wraith Corporation. Composed of some prominent members of the community (notably Jim Elson, Jimmy "EvilGenius" Sieben and Mackey "Avatar" McCandlish), they were producing a megaWAD that wasn't being released by id, Hell to Pay. Wraith Corp. helped finish out the rest of the megaWAD, giving the community another pair of commercial products, roughly analogous to Final Doom.