Check out this site: Dover Publications. They have several freebie coloring pages - many of which would be great for teaching leisure activities, as reinforcement activities, or as a fine motor activity. Several are also geometric shapes but they have several other types of pages.
Here are a few examples:


There is also a free email service you can sign up for - you will receive free coloring pages.You may find that the students enjoy the use of colored pencils more than crayons. You can certainly also use these for painting.









