ArtStation - Free 15 Alpha Brushes (4k resolution, 16 bit) - Cracks, Rock damage etc.
Blender Alpha Brushes Tutorial - Blender From Scrath Series
sculpting - How to get a extrude with alpha brush - Blender Stack Exchange
stone and rock alpha brush bundle - mgh3d
A pack of organic alpha brushes I made a while back! 1st image is what's already included, 2nd is what's coming tomorrow. It's gonna be a free upgrade for the people who
ArtStation - 45 stone and rock alpha brush bundle v2 + FREE tutorial | Brushes | Free tutorial, Tutorial, Creative assets
How to Use Alphas/Textures for Sculpt Brushes - YouTube