A fun craft activity for kids is to build spotted paper mushrooms out of construction paper and recycled toilet paper tubes. These are easy to build, so you could quickly create an entire forest of red mushrooms!
Paperfoldables.com is a great site where you can print free PDF templates for 3D paper models, both paper animals and paper people. Just print, cut, fold and tape. These crafts might be a bit hard for your preschooler, but if you build them together they can certainly have fun playing with the finished designer toys!