Dark Sun: Gulg
Psionic power is one of the few power sources on Athas that is universally excepted. Most people, even the most uneducated know of Psionic power. about 1 out of 10 people have some form of Psionic power (including wild talents). Still people still fear Psionic users, and are often afraid of being manipulated by them.
Wild Talents are the most often seen psionic power. While the vast majority of these talents manifest in comparatively minor ways, some wild talents are very powerful. For example, Kelira Legar drains youth from people, and Tomak can make his skin as hard as stone. Wilders are a form of wild talent that can actually be developed.
Other Psionicists (Psions, Ardents, Battleminds and Monks) learn to draw from from internal power. Psions due this through focus and intellect, Ardents through emotion, Battleminds through training and intent and Monks through precision in body.
A last, and fearful category of Psionics are those who develop power at a young age. There is no universal reason for this, and so it resembles wild talents, and yet the can be trained using other methods. These frighteningly powerful beings are little understood. They are often called Adepts.