All things are forms of several substances.
Democritus said reality is atoms and space.
Epicurus said reality is atoms and space qualified by a kind of spontaneity of atoms; motion is inherent in the atoms.
Empedocles said there are four elements: earth, weather, air, and fire, moved by love and hate.
Anaxagoras said there are countless elements matching the countless qualities of experience guided by an active element or mind.