Okay, I've been reminded! Taking a break from grindin on Warframe to go down my saved wad list for some of the best one I've played before. These will vary wildly from old classics, with vanilla compatibility, to modern wads with full usage of MBF21 specs, and anything in between. And some of these I haven't finished yet. Assume sequels and continuations when not explicitly mentioned too. Personal favorites marked in bold.
Ancient Aliens, Abcission, Ad Mortem, Akeldama, Alien Vendetta, Anomaly Report, Bring Back the 90s, Back to Saturn X, The Darkening, Dreamcatcher Apparatus (DBP 47), Doom 64 in Doom2, Doom the way id Did, Eternity, Eviternity, Freedoom, Into Sandy's Cities, JPCP, Liminal Doom, Lost Civilization, Machete, Memento Mori, Obzen, Requiem, Reverie, Scorn, Speed of Doom, Struggle-Antaresian Legacy, Tetanus, Violence, Antaresian Requiem, Baculus, Chronicles of Ghosttown, Crusader, Deathless, Eldritch Voyage, FlesHarmonic, Haunting Hollow, Hellbound, MindBlood Genesis, Nostalgia, Reverie, RYLAYEH, Scythe (and 2), Sunder, Sunlust, UAC Ultra, Unhallowed, Valiant, Vanguard, Whitemare.
Some of them I played with additional mods! And I have to mention again, Auger;Zenith.
Also yeah, Brutal Doom is cool and all, but it made way too many edgy impressionable 14 year olds think that this is all that classic Doom modding is about, and think the only way to play it is by loading gigabytes worth of mods into GZDoom and crash your computer in completely unbalanced combinations. While I DO enjoy doing that, there's 30 years of incredible Doom community creations to explore using good old vanilla gameplay sourceports, and I grew to appreciate that a lot more.