Materia? Making up elements is sort of unnecessary.
Not to mention, I'm gonna combine some of the elements anyway.
Like Gravity is Gravity/Space/Void. Poison is Poison/Acid/Plague. Mind is Mind/Spirit/Psychic. And I have Life/Death/Blood.
I can maybe get rid of Sleep/Dream/Nightmare. And combine Sand and Metal into Earth as Earth/Sand/Metal (rather than my mistake of Metal as Metal/Magnetism). Also, Darkness is Darkness/Shadow, so I may do Light as Light/Color/Beauty. I would do Light/Energy or something, but I already have Lightning/Thunder/Electricity.
And to counter Gravity/Space/Void, the element of Time, as Zale suggested. The two counteract, just like Light and Darkness.
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)