Supersymmetry
Supersymmetry is a scientific theory that says that when elementary particles (such as photons, electrons, and quarks) were formed at the beginning of the universe, matching kinds of theoretical "superparticles" were also created. If this theory is true, it would at least double the kinds of particles in the universe. If the universe has extra dimensions (M-Theory by Edward Witten predicts up to 11) then there would also be more ways to have symmetry and more kinds of superparticles.