Features:

Revamps mob drops to provide an alternative way of getting some of the rarest items in the game (such as Smithing Templates) and to make them renewable. Also adds more convenient ways to obtain certain items which can be a pain to get (such as Scutes).

Notable changes:

Wither skeleton: now has a 5% chance of dropping its Skull (+2.5% per level of looting) and a 2.5% chance of dropping a Rib Armor Trim! (+1% per level of looting)

Wither: now has a 40% chance of dropping a Netherite Upgrade! (guaranteed drop with looting 3!)

Piglin: now has a 0.5% chance of dropping a Snout Armor Trim or a Pigstep Music Disc! (+0.2% per level of looting)

Piglin Brute: now has a 55% chance of dropping a Netherite Scrap (guaranteed drop with looting 3!), a 5% chance of dropping a Snout Armor Trim (+2.5% per level of looting) and a 2.5% chance of dropping a Netherite Upgrade! (+1% per level of looting)

Warden: now drops 1-3 Echo Shards, 0-2 Disc 5 Fragments (both unaffected by looting) and has a 20% chance of dropping the Silence Armor Trim! (+20% per level of looting)

Pillager: now drops 0-2 Arrows (up to 5 with looting 3), has a 25% chance of dropping an Emerald (+15% per level of looting) and a 1% chance of dropping a Sentry Armor Trim! (+0.5% per level of looting)

Guardian: now has a 2% chance of dropping a Tide Armor Trim! (+1% per level of looting)

Elder Guardian:  now has a 10% chance of dropping a Heart of the Sea (+5% per level of looting), and Tide Armor Trim drop is now affected by looting (20% base +5% per level of looting) 

Shulker: now drops 0-2 Shulker Shells! (2 max, odds improved by looting)

Evoker: now has a 5% chance of dropping a Vex Armor Trim! (+2% per level of looting)

Vex: now has a 1% chance of dropping a Vex Armor Trim! (+0.5% per level of looting)

Turtle: now drops 0-2 Scutes (up to 5 with looting 3!)

Husk: now drops 0-2 Sand (up to 5 with looting 3) and has a 1% chance of dropping a Dune Armor Trim! (+0.5% chance per level of looting)

Bogged: now drops 0-2 Poison Arrows instead of regular arrows (up to 5 with looting 3) and a 1% chance of dropping a Wild Armor Trim! (+0.5% chance per level of looting)

Breeze: now has a 2% chance of dropping a Flow Armor Trim! (+1% per level of looting)

Less notable changes:

Bees and endermites: now have a 33% chance to drop a Honeycomb and Chorus Fruit respectively (+15% per level of looting)

Villagers and Wandering Traders: now drop 0-2 and 1-3 Emeralds respectively (up to 3 more with looting 3)

Wolves and Frogs: now have a 50% chance to drop a Bone and Slimeball respectively (unaffected by looting)

Mooshrooms: now drop 1-3 Red/Brown Mushrooms depending on the type (unaffected by looting)

Snow Golem: now drops a Pumpkin on death if it wasn't sheared beforehand

Stray: now drops 0-2 Slowness Arrows instead of regular arrows (up to 5 with looting 3)

Mod Compats:

Alex's Caves:            

Alex's Mobs:

Autumnity:

Buzzier Bees:

Caverns & Chasms:

Friends & Foes:

Guard Villagers:

Variants&Ventures:

Legend:

blue: 1.19.2+

yellow: 1.20.1+

green:    1.21.1