From http://bkc-od-media.vmhost.psu.edu/documents/tips1107.pdf
a natural play area:
water • sand • dirt • sticks • branches • logs • driftwood • grasses • moss • leaves • flowers • pinecones • pine needles • seeds • shells • bark • feathers • boulders • rocks • pebbles • stones
a playground:
balls • hoops • jump ropes • tires • sand • water • dirt • straw • boulders • rocks • stones • pebbles • buckets • cups • containers • digging tools • chalk • scarves • ribbons • fabric
an indoor environment:
blocks • building materials • manipulatives • measuring • pouring devices (cups, spoons, buckets, funnels) • dramatic play props • play cars, animals, and people • blankets • materials • floor samples • water • sand • sensory materials • recycled materials (paper tubes, papers, ribbons, caps, lids, wood scraps, wire, foam, cardboard) • plastic gutters • small plungers • tools • art materials (buttons, spools, natural and colored popsicle sticks, beads, straws, paints, brushes)