Lightning: Is a lot like fire, just more mobile and real masters can pull tricks with magnetism. Tend to be restless and active. Can get boosts from the power grid.
Sound: Is pretty flexible, though not strong at any one thing in particular. Support powers. Not automatically musically talented, you have to actually practice.
Darkness: IS NOT THE SAME AS EVIL. All about stealth and 'crowd control' (I.E. fucking with enemies by confusing or weakening them). Can learn to do curses.
Light: Long range laser beams! The more advanced spells are all about seeing through tricks and illusions. Good at finding things. Can always tell if they are being lied to.
Empathic: A strange one, their magic is extremely flexible but powered by emotions. In populated areas they're strong, near sites of tragedy their magic can get... Disturbing.
Wood: Plant manipulation and summoning plant monsters, lashing foes with vines and thorns, animating shrubberies into shields. Basically the same as beast, but in plant form.
Gravity: Pretty specialized, and basically turns into extremely potent and fine-grained telekinesis for really advanced users. Good at crushing monsters under their own weight. Can fly.
Metal: Conjure, shape and manipulate metal (though conjuring is an expert move). True masters can do crazy stuff with metallurgy, making magical superalloys. Out of costume they get a much lesser version of the Fabricate power's make-things intuition.
Illusion: Highly focused on deception and the more skilled users can create completely convincing fake worlds to deceive people in. Masters can make illusions become reality if they're convincing enough.
Transform: Marked out as similar to beast and wood, but more general and therefore weaker, though you can get really creative with it. Transform mages tend to get bored easily.
Space: Can make distances larger or smaller, can twist places into escherian nightmares or make near-invisible shortcuts. True masters can arbitrarily shrink and grow things, and six foot high spiders are terrifying. They never get lost.
'Other' specialties are incredibly eclectic and varied, but a general rule of thumb is that they tend to be highly specialized but powerful inside their narrow specialization. Some examples of 'other' are candy, bone, paper, stories, steam, the zodiac, the moon, guns, dolls, pearls, clocks, and string.