We love these thumb print drawings book by Ed Emberly. They are simple, easy and fun. I have only used stamp pad for this so far because it is less messy and easy to clean up afterwards but the book has suggestions for various mediums to try at the back. My boys still need my help doing this but hopefully soon they will be able to do them on their own too. I think this is a great way to introduce drawing to preschoolers. I just ordered Ed Emberley’s other book: Picture Pie on amazon. Looking forward to it!