A revised and expanded version of an earlier post that was pulled back to the surface by a superhero RPG I've been designing and the design questions that keep following me from system to system.
My favorite magic system is the spheres from Mage: The Ascension. Nine different effects (Location, Magic, Energy, Matter, Time, Spirits, Chance, Life, Mind) with the level determining the power of the effect. So a fireball could be just energy (strict heat); matter and energy (flame/lava/impact); location, matter, and energy (to make it appear somewhere else); and so on. You would work with the GM to determine what spheres at what levels would be needed for an effect that you describe.
My favorite magic system is the spheres from Mage: The Ascension. Nine different effects (Location, Magic, Energy, Matter, Time, Spirits, Chance, Life, Mind) with the level determining the power of the effect. So a fireball could be just energy (strict heat); matter and energy (flame/lava/impact); location, matter, and energy (to make it appear somewhere else); and so on. You would work with the GM to determine what spheres at what levels would be needed for an effect that you describe.