Who Is The Most Powerful Wizard/warlock/sorcerer Of All The Realms, Lands, Worlds?

Asked in Books, but figured I’d get better exposure in this category:
D&D Dragonlance: Raistlin
D&D Forgotten Realms: Elminster
MIddle Earth’s Gandalf
King Arthur’s Merlin
Harry Potter: Harry, Dumbledore, Voldemort
The Sword of Truth: Richard;
Rift War series: Pug aka Milamber
or your choice of
Which fictional character can control and wield the most powerful magic?
Note: people like David Copperfield, Harry Blackstone Jr, and Doug Henning don’t count…wrong type of “magicians”