In Garth Nix's Sabriel Trilogy, magic takes two forms: Charter Magic and Free Magic. They are basically White and Black Magic, although calling them that would have probably been too cliche.
Charter Magic is connected to The Charter, a force that flows over and through everything natural and man made. Beyond its supernatural magical manifestations, the Charter is seen as providing the natural order to the world as well. In fact, it could be seen as a type of non-personalized diety, with characters often making such references as "Charter Knows".
The Charter is best manipulated by Charter Mages, people who have a special Charter Mark on their foreheads, and are able to draw charter marks, although charter marks are not neccesarily written. Sometimes they are whistled, spoken, gestured or merely thought, and they can be embued into an object. While the narrative is a little vague, they are usually in written form, as shining characters that move of their own will, or float through the air. There are probably at least a few tens of thousands of individual Charter Marks, although even a skilled mage may know only a section of them.
Opposed to Charter Magic is Free Magic, Magic that does not bind itself up into the order of things. With a few notable exceptions, most Free Magic is evil, and very evil. Free Magic creatures usually prey upon human beings, consuming both their physical bodies and their spirits. Free Mages are human beings who would attempt to control Free Magic, and never for good purposes. The most feared of the Free Mages are the Necromancers, who attempt to control and reanimate the Dead. Interestingly, Free Magic is always accompanied by a "metallic smell" or "metallic taste", which is also the characteristic taste that certain very scary hallucinogenics will impart to the taker.
The origin of the two strains of magic is revealed as the series progresses. Originally, all magic was free. There were nine free spirits of magic, with one, the most powerful, being a spirit of destruction. Seven of the spirits underwent a agical ritual to bind this great spirit. Five of them later subsumed themselves as entities, creating the five entities who would serve to bind the charter together: The Royal Line, the Wallmakers, the Clayr, the Abhorsen and the Charter Stones. Two of the entities remained Free Magic entities, and went into mystic sleep, while still remaining loyal to the idea of the Charter. An eigth being was neutral in the conflict, and was punished with being magically bound. The ninth was succesfully bound and buried far underground.
Although only split into two divisions, Garth Nix presents this system of magic as very detailed, and as if it possessed a depth of realism.