I have coloring books and children's activity books. Got them from the dollar stores. Different size pics and easy to trace. Also have "CRITTERS Dancin' in the Moonlight" by Brandywine Design. I use the activity and coloring books the most. The outlines are so much bolder and easier to trace with freezer paper. I paid more for "CRITTERS' than I did for the dollar books. but still not waste of money. One thing about the activity books is if you want you can reduce the copies for smaller versions.