This Rocks! is available for 1.21.1 and 1.21.5 on Fabric and there is also a Neoforge port. See it on Modrinth
What's the first thing you usually do when you start a new world? Punch a tree? Not anymore! With This Rocks!, you can start picking up sticks and small rocks. Combine the rocks to get cobblestone, and you have everything you need to make a stone pickaxe--except for a crafting bench. OK, go punch that tree now.
This Rocks! makes the world feel a little more alive by adding little things all over the place. Most of them are useful, especially when you don't have anything. They're also replaceable, just like grass, which means that you can build right over it and it will go away. But can you ever have enough sticks? I know I can, especially now that sticks drop from tree leaves when you break them.
This Rocks! is a fun, simple mod that I like to add to my worlds both for the way it looks and for how useful it can be.