Mature steam, first gasoline, the cusp of electricity - a curated Create 6 survival era-pack: rail empires, oil fields, physics airships, industrialized enchanting, and ruins worth an expedition.
The big one - the full Roaring 20's set in one release (146 mods + 4 resource packs):
56 custom quests in 12 chapters: the Age of Steam, the Expedition Society's frontier arcs, the Madman's Laboratory, the Gatsby Cafe & Derby Day, the Alley Rats gang career, and more.
Terralith + Tectonic worldgen, the casino wave (Charta card tables, Jackpot slots), Immersive Engineering, cameras & gramophones, wildlife, YUNG's structures, and the whole Create addon family.
Custom death rules: corpses become lootable skeletons; bodies holding items never despawn.