The venerable Electromancer, while not being all powerful, is certainly versatile. For somewhat more outlandish:
Vectormancer, perturbs vector fields, especially the direction of travel of objects.
Hemomancer, aka, the blood bender
Hermetomancer, magic bender, twists other magics into new forms but is not herself a source of power.
Jurismancy, controls laws... is changing a law of magic a violation?