Peaceful Progression
Makes blocks/items/dimensions which require hostile mob drops available in peaceful difficulty
Effigy Altar
Spawning deep underground, Effigy Altars allow you to craft boss effigies instead of having to fight them. Cartographer villagers can help you find them!
Improved Sniffer loot pool
Sniffers can now dig up new plants in soul soil and gravel, and a number of mob drops out of sand
Fossil ore
Spawns in stone, deepslate, and soul soil to make up for the lack of skeletons
Brimstone ore
A key ingredient in gunpowder and in fueling the Effigy Altar
Enderclams
One of two added mobs, provides an alternate source of Ender Pearls including when in the End
Dragon Effigy Recipe
Use the dragon effigy to create an end gateway or get dragon's breath from a cauldron.
Wither Effigy Recipe
Use the wither effigy to get a Nether Star.
Elder Guardian Effigy Recipe
Use the elder effigy to get the Elder Guardian's loot.
Totem of Undying Recipe
Raid Effigy Recipe
Use the raid effigy to get randomized loot that you would get from a raid.