Manipulation magic: you don't actually see and hear what your eyes and ears see and hear. You see and hear what the brain interprets from your eyes and ears. Perhaps your magic can interfere with signals sent to your brain making you see and hear things that aren't there. Alternatively maybe your magic can bend light to make things invisible or just look different then they actually are.
Destructive magic: matter cannot be created or destroyed but it can be changed from one form to another. Perhaps your magic play on that. Some sort accelerated entropy magic. Or you want to make your mages is really powerful according to Einstein matter could be converted into energy. If you are mages could convert magic to energy with their mind and/or a magic spell then they would be walking nuclear bombs.
Restoration magic: the ability to control someone's body on a cellular level would give your mages the power to cure disease and poisons. They could simply force your cells to produce the correct antibodies or chemicals to counteract whatever disease or poison you had. They might even be able to grow back limbs by forcing your body to produce stem cells and then forcing the stem cells to form a new limb.
More Manipulation magic: maybe your mage or magical creature could release some kind of hallucinogenic hormone into the air. This could cause their enemies to hallucinate their worst fear or greatest desire depending on the hormone used.
More Destructive magic: it's possible for creatures ( such as the electric eel) to have organs that generate electricity. It's also possible for Organic creatures to produce chemicals that when combined together will ignite. This could serve as a biological means for certain "magical" creatures to generate fire or lightning.