A week ago I uploaded a single rock formation. I have since then made 5 more. Here they are in a single package. I have also made several prints and painted them pretty. Now fill your game boards with scatter rocks.
All the rocks are mostly hollow. You can scale them up and down as you want. Some have built-in support. The others don't need it.
I made these rocks by sculpting them by hand in Blender. With the excellent rock brushes from Blender Guru:
https://www.blendermarket.com/products/the-rock-essentials
I only have the brushes. These are not the rocks included in the big package.