Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download AAA Terrain by Anio Free.
AAA Terrain by Anio v1.0
It’s a powerful shader for Unity’s terrain.
They allow to you create a NextGen surface for your terrain using a DirectX 11 tessellation.
This material support a real-time painting using a 4 brushes on one terrain.
Our algorithm using a LOD for calculating a count of an additive meshes. That mean that your terrain will NOT require more calculation than needed.
For start you just must set a material based on our shader to your terrain and set a displacement maps.
Shdaer fully support PBS:
Optimized for work with atlas maps.