Types of Magic
According to Sizemore Rockwell's explanation of Erfworld magic to Parson Gotti, there are eight major classes of magic, each defined by one of the eight combinations (either present or absent) of the elements Life, Motion, and Matter:
These major classes are:
Parson is skeptical of whether this represents the real theoretical basis of Erfworld magic (it reminds him of "that crap about the four basic elements that people believed for centuries just because Aristotle said it"), but it is the best available systematic description.
In each discipline there is a certain number of spells it is possible to cast.
Natural Magic describes powers that are not initiated by a caster, but are rather an innate ability of Erfworld units, such as flight or digging. For example, a scout unit's ability to report information (such as a Doombat's ability to relay its sightings to Vinny) is a function of Natural Thinkamancy.