While not a terrain overhaul, 1.21.50 significantly changes the audio atmosphere :
Combining the Heavy Core from a Trial Chamber with a Breeze Rod, you can craft the Mace to deal massive "smash" damage from above. The Crafter: Minecraft 1.21.50 APK
Place in a horizontal row in the crafting grid. This will produce 3 Paper . Uses for Paper Books: Combine 3 Paper and 1 Leather to make a Book. While not a terrain overhaul, 1
Resin Clumps can be smelted into Resin Bricks, which are used to craft a new vibrant orange block set including stairs, slabs, and walls. Armor Trims: While not a terrain overhaul