Make a Stick Person! Heck, make a Stick Community! Fun, open-ended craft that preschoolers (and toddlers) can do all by themselves, and work on their fine-motor skills at the same time. Plus you get some free DIY dolls to roleplay with at the end!
This is a great example of MATERIAL RICH ENVIROMENT from- Empowering Pedagogy For Early Childhood Educators ideas for collage tables (the pics on the site are quite small. Open pics in new tab to easily see larger pictures.