Doom Series
Nightmare Without Respawn Pack-v2.0
https://drive.google.com/open?id=1grVkg ... W984hBWyEf
Spoiler:This set focuses on removing respawning monsters from nightmare difficulty and providing altered damage rates and monster health, along with modes that remove large ammo pickups. (The low ammo modes my conflict with mods that use large ammo pickups as unique pickups when playing on those modes.)
Doom Wad Specific
Brutal Doom
BrutalDoom Low-Ammo Nightmare-v2.0
https://drive.google.com/open?id=1I0Juo ... OkCDRxAwnR
Spoiler:This one revolves around replaces large ammo packs with smaller ones similar to realism mode. (Designed for Version 21 Gold)
[Credit to SGtMarkIV and co.]
DUMP 1-3
DUMP Difficulty Bypass-v1.0
https://drive.google.com/open?id=1__6e1 ... 78ZSGa52i-
Spoiler:This is designed so that you can play all 64 maps on difficulties other than Nightmare. (Results may vary)
[Credit to TerminusEst13 and co.]