This is a copy of the original paste by an /mcg/ anon, still (semi-)actively updated here, with some modifications. Mirrors are all MEGA links.
MultiMC-compatible Blightfall: One of the most polished minecraft modpacks, you should know what this and played it already. If you don't, it's an absolute must.
mega
Retro Magitech: 1.12 Techno [IE+Nuclearcraft]-magic (TC6) pack focused on cross-mod interaction, very well polished and scripted.
curseforge
Gregorious: Iter Vehemens ad Lutum [AKA FUGLutum!]: (GT6+Botania+TC) GT6 pack with heavily scripted GT cross-mod interactions and mob sieges (ESM/SpecialAI/NoShelter). Progress from the stone age to lasers and expand your factory while fighting mobs with tech, magic and gay-ass flowers.
curseforge
Technodefirmacraft [TNFC]: 3.7.1 One of the best TFC modpacks, a tech-oriented pack that really breathes new life into TFC. Forked from ATlauncher to be multimc-compatible.
mega
Gregblock Lutum: Skyblock themed Old GT6 and botania
dropbox, mirror
Per Fabrica ad Astra [PFAA]: [Modpack REQUIRES pregenning the world because the coremod fucks worldgen times into oblivion, you've been warned] TFC modpack with scripted recipes, a very decent questbook with in-depth explanations and a story to follow to boot. Comes with some weeb mods (shincolle et al)
mega
Glory Days: a 1.7.3 beta modpack by anon. Comes with all your favorite ancient tech mods, wireless redstone, the season mod and much more.
Screenshot of modlist:
mediafire, mirror
What happens when you combine Blightfall and Gregtech5? Well, someone decided the world needed to know (P.S. this is a joke pack).
dropbox, mirror
Thaumic expanse: Finally a mod that makes the TC4 thaumonomicon window bigger. Truly a godsend.
dropbox, mirror
Grimoire of Gaia: Touch the Big Booby edition (1.12 only)
mega
TFC Addon to reduce armor levels, health and mob damage to vanilla levels (removed the x50 multiplier on everything)
catbox, mirror
Castlefag's map: Very well polished castlevania-inspired adventure map, for 1.7.
mega
General purpose skybox:
mega
Skyblock/Sky island-themed skybox:
catbox, mirror
Serene Seasons for 1.7 (Recompiled bugfix for fixed glass textures)
catbox, mirror
Monstergirl torturer anon animal-to-cute-monstergirl model swap textures (Requires 1.8.9+ [1.12] optifine for model swapping):
Cow: anonfile, mirror
Chicken: anonfile, mirror
Sheep: anonfile, mirror
ToxicJungle resource pack (PP + substrate, textured are changed frequently)
anonfile, mirror
TFC+ with Vanilla values edit, to streamline the 1.12 TFC+ Mods experience.
Playable File: catbox, mirror
Deobfuscated: catbox, mirror
Source: catbox, mirror
KC(Thaumanon)'s guide to thaumcraft addons: Essential TC4 addons knowledge, complete with personal forks. A must read for any thaumaturge.
https://github.com/KryptonCaptain/Misc-Files/blob/master/TC4 addon list.md
Modpacks removed from the original pastebin.
/mcg/'s Tame The World (quest-driven 1.7 fighting-exploration (ruins, dungeon mobs) magitech (IE+ Reika+ TC addons+ Botania+Witchery) pack with lots of 1.7 exclusives)
mega
Infitech 4U (/mcg/ Infitech 2 updated to GT5U and forked with QoL changes along with saner edits and cuts)
mega
Actively curated by anon at:
https://pastebin.com/YedwJKFU
(refer to this paste for the newest version)
Certain versions of modpacks updated or rehosted with mega.
Also includes packs removed from >thatgayfaggot's listing.
Duplicate pastes/guides removed.