Seeds, nuts, shells, rocks, ...
See the Found Chapter for more instructions, hints, tips, and ideas.
Beaches and forests are wonderful places to find all kinds of interesting objects. There are shells, sharks' teeth, rocks, driftwood, seeds, and egg cases. Wash or clean the object thoroughly and let it dry. You might want to give it a coat of Thompson's Water Seal or clear acrylic spray finish to preserve it. Mount it on a background if you want.
You could glue sand to the background with Tacky glue to make it more natural looking. But this would be a lot messier.