Key: Strange Tales Volume 2 - ST V2

Additonal Key: Fantastic Four - FF

His defenses, survive lightning - ST V2 2

Black Magic (the opposite of White Magic, which he is pledged to as the Sorcerer Supreme) permits him to summon the dead - ST V2 6

Energies released from an emotional outburst (before he trained in Black Magic) tear a room apart - ST V2 8

Even as a novice of Black Magic he could banish Ghaszaszh Nyirh and destroy his entire ancient monolith-temple, an Old One who served Shuma-Gorath - ST V2 10

Summons an army of elemental spirits and forces them to fight for him - ST V2 11

Flies by Dragonfire across numerous realms - ST V2 13

Reaches a realm described by Kaluu (A sorcerer on par with the Ancient One and Strange's master in Black Magic) as deeper than any mortal has ever treaded. The realm is so great in scope that even beings like Mephisto and Satannish are likened to mice in a great temple. It was killing Kaluu by virtue of simply being in the realm. Strange is unfazed - ST V2 13

Defeats and absorbs the power of Arioch, a Lord of Chaos and lieutenant to Shuma-Gorath, in his own realm, wherein he boasted of strength that was limited only by his imagination (very much similar to how dimensional lords are effectively omnipotent in their own dimension, except that Arioch's dimension is far greater in scope than those of say, Mephisto) - ST V2 13

One of, if not the THE battle(s) of Strange's career, in my humble opinion. Dr. Strange, having absorbed the power and ego of Arioch, comes face-to-face with none other than Shuma-Gorath himself. He faces down the Lord of Chaos, Absolute Ruler of Hundreds of Dimensions in his own realm, deeper than even Arioch's own and where he is effectively all-powerful. As always, you can count on the Sorcerer Supreme!

His shields block a full-on attack from Shuma-Gorath - ST V2 14

Severs one of his limbs - ST V2 14

Was draining power out of Shuma himself - ST V2 14

Cancels out Shuma-Gorath's mystic attack on the entire planet with his own spell - ST V2 14

Blocks Shuma's attack despite letting his guard slip too much - ST V2 14

Their conflict was threatening to collapse all the Nether-Realms - FF 314

Destroys Shuma-Gorath by hurling Shuma's own planetary voodoo doll into his eye, shattering him - ST V2 14

In an act of sacrifice, Strange stabs himself, and in the process shatters his own ego to prevent himself from ever becoming the next Shuma-Gorath - ST V2 14 / 15

His ambient energies after the battle would have shattered entire galaxies with their natural discharge - ST V2 15

He did what even Agamotto did not - ST V2 15

With his ego rebuilt by Enitharmon, Dr. Strange can now stand again in the light, having mastered both White and Black Magic - ST V2 17

Gives Victoria Bentley all the mystic power he drained from her before fighting Shuma, and more - ST V2 18