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!
Nature Mandala ~ Take your storytime kids on a nature walk and build a collage out of what you find! Maybe try this as an excursion. Or collect heaps of things from nature, hide them around the room and go on a treasure hunt