Yakub's pack:

Core game changes:

Biomes O' Plenty (50+ new biomes)
Built in porformance mods and shaders (Oculus, Rubidium etc.)
Lots of new structures
BOTW like spirt orb system to increase health with satues found in villages
Aircraft and ships
Lots of new mobs
Voice chat and other server mods
Lots of new building mods
Gambling (Stand on a Diamond Block, equip a Diamond Sword in main hand slot and begin to alternate it from main hand to offhand (press F)
Construction wands to build faster
A camera
Better Combat mod that gives better animations and the abilty to hold click to attack
Sitting
Upgradible furnaces
Bounty boards found in villages
Craftible portals to spawn waves of mobs for loot
Vending machine's to trade
Lots of new food, beer, wine and tea (farmers delight etc.)
Estrogen

Dimensions:

The Aether (glowstone portal, ignite with water bucket)
The Twilight forest (4x4 dirt frame with flowers around and water the middle, throw dimond in water)
The Undergarden (craft a catalyst and use it to ignite a portal made of stone bricks)
The Midnight (killing some mobs creates rifts)
Blue Skies (Find a Gatekeeper and trade him a book for his journal)
Good Night's Sleep (find hope/dispair mushrooms craft strange bed)
Ad Astra (Craft in game guidebook)

Tech mods:

Magic mods:

Blood Magic (craft in game guidebook)
EvilCraft (craft drakened apple feed vinilla animal apple throw book on its soul)
Ice and Fire: Dragons (find manuspricts and use them to craft in game guidebook)
Occultism (break grass untill you get Demon's Dream Seeds and use them to craft in game guidebook)
Mahou Tsukai (craft in game guidebook)
Iron's Spells 'n Spellbooks (https://iron.wiki/progression/)
Ars Nouveau (https://www.arsnouveau.wiki/)

Bosses:

Yakub's Pack