View less significant changes
Cows
Cold Cows might drop 1 extra Leather on death.
Warm Cows might drop 1 extra Raw Beef on death (Steak, if killed by fire).
Chickens
Cold Chickens might drop 1 extra Feather on death.
Warm Chickens might drop 1 extra Raw Chicken on death (Cooked Chicken, if killed by fire).
Temperate Chickens might lay 2 eggs at a time.
Chickens no longer spawn in Bamboo Jungles, or Swamps (Ducks do instead!).
Elder Guardians
Their beams are much less visually obtrusive.
Now give Mining Fatigue more persistently, and up to 75 blocks away (instead of 50). The Elder Guardian's ghost animation will not play if Mining Fatigue is simply restored instead of applied for the first time.
Now drop a Gate Key.
Guardians
Can be converted to Elder Guardians via lightning.
Spawn much less often to avoid Ocean Monuments being impossible.
Their beams are much less visually obtrusive.
Drowned
Might be replaced with a Sunken Drowned if they spawn below Y=46.
Piglin Brutes
Can be converted to Zombified Piglins via lightning.
Wardens
Now drop 1-3 Echo Shards on death (amount boosted by Looting).
Cat
If names "Ethel" will spin anticlockwise.
Frogs
Now drop 1-2 Frog Legs of their coresponding variant on death.
Trader Llamas
Now spawn with Chests attatched, and some loot inside.
Possible loot chest items: Feathers, Sticks, Moss Blocks, Bread, Milk Buckets, Emeralds, Emerald Ore (regular variant only), Melon Slices, and Name Tags.
Rabbits
Now drop 1-3 Rabbit Hide on death instead of 0-3 (amount is still boosted by Looting).
If named "The Killer Bunny" will become the Killer Bunny variant.
Creepers
Now have Otherside as a possible Music Disc drop when killed by a Skeleton.
Vindicators
Now have a chance to drop a Lapis Lazuli on death (chance boosted by Looting).
Fishing Bobbers
Now get destroyed in Lava (unless using the Fireproof enchantment, see Enchantments).
Bees
Are now 40% smaller.
Witches
Have 15 extra health points.
Husks
Now drop 0-2 Sand on death (amount boosted by Looting).
Rarely drops a Copper Ingot on death instead of an Iron Ingot.
Shulkers
Are now considered arthropods, since they share many similar features to arthropods.
If named "jeb_" will cycle between colors.
Zombies
When spawning below Y=21, might hold a Pickaxe (Wooden, Stone, Golden, or Iron, with Iron being the rarest). These Pickaxes have a drop chance of 60%.
Allays
Can be converted to Vexes via lightning.
Hoglins
Can be converted to Zoglins via lightning.
Magma Cubes
Can be converted to Slimes via lightning.
Ocelots
Can be converted to Cats via lightning.
Spiders
Can be converted to Cave Spiders via lightning.
Some spawn locations might be replaced by Baby Spiders.
Villagers
Have randomised names (with some super rare special names, too!).
ALL MOBS
Naming any mob "Silence" causing it to not play noises.
Players
Drop Player Heads on death.
Cats
Can now be bartered with. See Cat Bartering Mechanics.
Piglins
Can now give the following items from bartering: Nether Quartz Ore, Snout Banner Patterns, Pigstep Music Discs, Crimson Curries, Warped Curries, Netherite Upgrade Smithing Templates, and Enchanted Books (Midas Touch (see Enchantments)).
Give Dried Ghasts much less often when bartering.
Some spawn locations might be replaced by Piglin Shroomists.
Can be converted to Zombified Piglins via lightning.
Wandering Traders
Have randomised names (with some super rare special names, too!).
Might now sell the following items: Diamonds, Disc Fragments (5), and the following ores (both regular and Deepslate variants): Coal, Copper, Iron, Gold, Restone, and Lapis Lazuli.
Can be converted to Witches via lightning.
Ender Dragons
Now drop a Dragon Head on death.
Now creates a Dragon Egg every time it dies, not just the first.
Cave Spiders
Might now spawn anywhere Spiders can spawn below Y=21.
Some spawn locations might be replaced by Baby Cave Spiders.
Pigs
Now give birth to 1-3 baby Pigs (and very rarely 4) instead of 1.
Wolves
Wolves have a 1/1200 chance of spawning as the secret Asher Wolf variant.
Asher Wolves have 5 extra health points and deal 1 extra point of damage.
Woods Wolves have 3 extra health points.
Pale Wolves can fall up to 3 extra blocks safely.
Black Wolves deal 2 extra points of damage.
Chestnut Wolves are slightly smaller and might give birth to 2 Wolves instead of 1.
Striped Wolves move slightly faster.
Spotted Wolves can jump up an extra block.
Rusty Wolves take much less knockback.
Ashen Wolves deal more knockback.
Snowy Wolves can follow targets from an extra 32 blocks away.
Sniffers
Can now sniff in Sand, Red Sand, Soul Sand, Soul Soil, Farmland, Crimson Nylium, and Warped Nylium.
Now find Pitcher Pods twice as often as Torchflower Seeds.
Can now sniff up Tall Grass
In Lush Caves, can now sniff up Glow Berries, Spore Blossoms, and Small Dripleaves.
In Taiga-type biomes, can now sniff up Sweet Berries and Large Ferns.
In Pale Gardens, can now sniff up Open and Closed Eyeblossoms.
In Deserts, can now sniff up Cactus Flowers.
In Crimson Forests, can now sniff up Crimson Fungi.
In Warped Forests, can now sniff up Warped Fungi.
In the End dimension, can now sniff up Chorus Flowers and Chorus Carrots.