Magic
Magic based on an organized model of universal principals. Specific magical effects are instances of interactions between these principals. Mage and Ars Magica are good examples of this.
Structure: Divisional/Scientific
Magic dependent upon particular knowledge of an enormous number of topics, which may themselves be infinitely divisible. Practitioners will tend to specialize, and there are few universal principles. FUDGE uses this type of system.
Along with: Scholarly
Magic with highly variable outcomes based on the practitioner's success. The Spellsinger series of books and GURPS Rhyming magic both fit this model.
Character: Unpredictable
Magical energies and procedures may be used to permanently enhance the power of the practitioner. AD&D's Dark Sun setting includes this concept.
Spice: Personal Empowerment
Creation of potions and other single-use magic items.
And: Alchemy