Hey,
The powers themselves can range from control of the elements, to mind reading, to shape shifting.  As long as it is limited from powers leading to problems like immortality or something with no weaknesses.  So for shape shifting I would prefer someone choose one animal or one species instead of turning into everything.  For example, Asher is sees spirits and can read emotions, but at the moment he is blind.  Another character I am making has the ability to control light and shadows.  Pretty much anything as long as you can't destroy the asylum in one swoop. :)