I uploaded a stone and rock model to my patreon account, here is the link:
https://www.patreon.com/posts/22764618

You can use the models as you like, even commercially.

The stylized material that I used with Substance Painter for texturing is made by a fellow artist 3dEx, you can get it from his gumroad here:
https://gumroad.com/a/400077939/gpOYt

See my social profiles here
G+: https://plus.google.com/+JayAnAm
Twitter: https://twitter.com/jayanamgames
Facebook: https://www.facebook.com/jayanamgames
Patreon: https://www.patreon.com/jayanam

Production Music courtesy of Epidemic Sound: http://www.epidemicsound.com