Have you tried Macrock? It generates random rocks exports as DXF which you can import into library objects to create a collection of rocks.
Here is a link...
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics
