These are some objects that you may encounter:
Trees are scattered upon the landscape. With the Woodcutting skill logs can be harvested from them.
Fish and other sealife can be caught upon the shores of lakes and streams.
This item has no use whatsoever. Hopefully Jagex will make a use for them. It is dropped by EARTH ELEMENTALS.
Ashes are left over from fire of Imps. Required for Witch's Potion Quest. Ashes are useless otherwise.
An item that is dropped by Imps. These objects are completely useless.
Rubble that is obtained in the new tutorial, this is also useless and is required to be dropped before exiting the tutorial.