Painting rocks rocks! For more:

could be lovely preschool activity, to make some painted rock pictures

DIY 'pebble people'. There is a store with that name in Solvang, California - selling these pebble decorations and other handcraft - I visited it back in the 70ies.

Rock people garden statues DIY decor DIY Garden Trinkets - Awesome Ideas, Projects and Tutorials! Including, from 'instructables', this creative 'garden thing' project with rocks.