Nice try, but the One-Above-All wasn't created by Stan Lee...he was created by Steve Englehart in Dr.Strange #13, April 1976.
But the Living Tribunal does bear Stan's mark, and was created by him in Strange Tales #157, June 1967; bearing in mind that current continuity holds that the Living Tribunal is only subordinate to the One-Above-All in terms of authority etc, then the answer to "who is the most powerful marvel character created by Stan Lee?" is The Living Tribunal.
Incidentally, the One-Above-All character is possibly identical to the Celestial of the same name who appeared in Eternals #7, January 1977; the Celestial "One Above All" was created by Jack Kirby, as was Galactus for any one out there wondering.
One of the most powerful characters created by Stan Lee is "Galactus." Known as the Devourer of Worlds, Galactus is a cosmic entity with vast cosmic powers that make him a formidable force in the Marvel universe.
'Deadpool' , a Marvel comic-book character , was created by artist Rob Liefeld and writer Fabian Nicieza .
The Skull, a supervillain character in Marvel Comics, was created by Stan Lee and Steve Ditko in 1965. He first appeared in "Tales of Suspense" #79.
Hera, a character in Marvel Comics, was created in 1964 by writer Stan Lee and artist Don Heck, first appearing in "Journey into Mystery" #116. She is based on the figure from Greek mythology who is the queen of the Olympian gods.
The one and only Stan Lee
Stan Lee and Steve Ditko created the fictional super-villain called Mysterio (Quentin Beck). The evil character is an enemy of Sipder-Man in Marvel Comics.
Stan Lee did not create Superman. Superman is in DC comics created by Jerry Siegel and Joe Shuster. Stan Lee is part of Marvel comics. :)
Spider-Man was created by writer Stan Lee and artist Steve Ditko, and first appeared in "Amazing Fantasy" #15 in 1962. The character has since become one of Marvel Comics' most iconic and enduring superheroes.
The Hulk was created by writer Stan Lee and artist Jack Kirby, and first appeared in the comic book "The Incredible Hulk" #1 in 1962. The character has since become a popular superhero in the Marvel universe.
The original Publisher of Marvel was Martain Goodman, (back then it was called Timely Comics in 1939), but the main creator of heros was probably Stan Lee this was when the name marvel was given to the company Timely in 1959, Marvel was named by Stan Lee.
Captain Mar-Vell The Alien Kree Officer of the Kree Empire in the marvel universe was created in 1967 by Stan Lee and Gene Colan. The first issue came out in December. The DC version of Captain Marvel came out in 1940, but the character itself was created a year earlier in 1939 by Beck and Parker
1. apocalypse 2. Thor 3. galactus 4 silver surfer 5. Beyonder 6. Ghost rider 7. Kronos 8. Master order 9. destroyer. 10. Captain Marvel hulk is the 38 most powerful