Power categories???
How would you devise the powers that appear in the series?
Piper for example, I would put into the "molecular manipulation" category. Her ability to affect molecules is self explanatory, but would powers like invisibility fall into this category?
Then there's Phoebe, who we are told is in the "Mentals", her premonition could be classed as mental as could her empathy, but levitation is not a mental power (despite what remus said!) So where would that power fit in.... "Physical" maybe?
Prue's astral projection and TK are defiantly "mental".
Where would Paige's powers slot in? Her TK orbing is like Prue's so would be "mental", but orbing is "Teleportation/transportation".
Super Strength would be a "physical" power.
Then there's lightning throwing and fire control. Would these be "Elementals"?
How are powers allocated? How many groups would there be?