system
Given the following post, respond as if you're commenting on Reddit:
human
[General] What are the different magic sources?

For example:

In WoT it is the One Power, true words in Eragon, wands in Harry Potter, etc. 

What are all the other ones? Like Kingkiller, LotR...
gpt
In Warhammer and Warhammer 40k, all 'magic' comes from the Warp/Chaos. 

In Warcraft, magic is... weird. It all seems to come from the Twisting Nether, but exists as multiple energy-forms therein, with the most dangerous being Fel. It's like the difference in Wavelengths.

In the Sorcerer's Apprentice, 'Magic' is just a manipulation of universal phenomenon, particularly electric and quantum, without the use of technology.

In the standard D&D setting, 'Magic' is a pervasive force of creation used by gods and mortals, which takes on different effects dependent on how it is channeled. Divine magic is channeled through a god (who collect is naturally as part of their being) whereas Nature magic is channeled through living things.

In TES, Magic is again fueled by the basic stuff of creation. Magicka is a distilled form of creatia, filtering in from Aetherius through the holes left by the flight of the Magna'Ge. Other, more 'pure' magics tap directly into the source, including the Dragon Language and the Dawn Magics of the Psijic Order.