Spoiler warning: This article contains spoilers for Doctor Strange in the Multiverse of Madness.
Doctor Strange in the Multiverse of Madness earned its title by visiting an array of different realities. Many only appeared briefly in the chaotic scene where Doctor Strange and America Chavez tumbled through the multiverse before landing in Earth-838. Major hints of the past and future of the MCU lie in these brief glimpses, though, including possible universes the franchise revisits.
The best universes in Doctor Strange in the Multiverse of Madness experiment with the elasticity of the multiverse concept by splashing through realities composed entirely of paint. They also show brief teases of realms that possibly connect to Marvel Comics figures fans have long anticipated seeing on screen, including powerful figures like Mephisto and The Living Tribunal.
Stark Drone Universe
A mysterious universe in the sequence features massive Stark drones similar to those used by Mysterio in Spider-Man: Far From Home. They appear to construct some massive object of unknown purpose. The mystery of the drones makes this one of the best universes in the movie.
Nothing else appears in this universe besides the drones, and it's possible that they are all that exists there. Another possibility exists through their connection to Tony Stark. A variant of Ultron may command these drones, or perhaps The Vision.
Universe Between Universes
The movie establishes a universe that exists between all realities in the multiverse. The Book of Vishanti resides in this nebulous realm, making it one of the best universes in the movie and key in the MCU's vast multiverse.
The Book of Vishanti ranks among the most powerful weapons in Marvel Comics thanks to its extraordinary mystical power. The book appears in the opening sequence of the movie when the Defender Doctor Strange and America Chavez race to reach it.
Ancient Ruins Universe
Doctor Strange and America Chavez tumble out of Earth-616 through a series of universes. A key one in the sequence contains ancient ruins floating in a broken space that recalls somewhat the realm of Olympus just introduced in the Thor: Love and Thunder trailer.
This universe counts among the most intriguing in the movie as Olympus may suffer at the hands of Gorr the God Butcher. Comic book fans know Gorr the God Butcher kills gods from every pantheon in the Marvel Universe and the ancient ruins glimpsed in Doctor Strange in the Multiverse of Madness might be a dark glimpse of the future.
Sinister Strange Universe
The universe Doctor Strange and Earth-838 Christine fall into after Wanda's rampage disintegrates in a fashion recalling the fate of the What If..? Doctor Strange's reality. The Sinister Doctor Strange resides in this reality, seemingly alone. The intriguing ruin of this universe hints at the possible fate of Earth-616.
This universe crumbles into nothing, likely because it is the universe that Earth-838 Doctor Strange dream-walked into. The incursion he created between them killed everyone in this universe. At the end of the movie, Earth-616 Doctor Strange learns he created an incursion as well.
Bone Universe
A frightening and intriguing universe sails past as Doctor Strange and America Chavez tumble through the multiverse. A hellish landscape appears behind them, with everything constructed of human bones. This realm hints at the existence of Mephisto.
Mephisto ranks among the most powerful magical beings in Marvel Comics. Fans speculate about his MCU debut often and this brief tease of a demonic dimension - perhaps seen again at the end of the movie as America and Wanda fight - could be a clue to his MCU future.
Paint Universe
The movie really exploits the possibilities of the multiverse in one brief scene. Strange and America fall into a universe made entirely of paint and become globs of wet paint themselves for a moment, creating the movie's most unique dimension.
The paint universe flies by but does seem to have some structure. Architectural elements appear in the background of the shot, though little can be discerned from them. America notes it wouldn't be as easy to eat in that universe as it is in others, though.
Cubic Universe
A bizarre universe in the movie takes advantage of the multiverse premise in a unique way. Strange and America fall into a universe where the physics appear to organize everything into cubic shapes. Both characters fragment into cubes, right down to their teeth.
The city below them appears to be a cubic Manhattan, suggesting everything physical in this universe manifests this way. This reality zips past in the movie, but its inherent strangeness makes it a great universe for What If..? to visit in season two.
Animated Universe
The movie crashes through all kinds of different universes and mediums. For a brief moment, Strange and America transform into two-dimensional animated versions of themselves, reminiscent of the art style of Spider-Man: The Animated Series.
The animated universe differs from the exact style of that series and other Marvel animated shows, but the movie wears its love for those shows on its sleeve. When Professor X appears in Eath-838, the theme music for X-Men: The Animated Series accompanies him.
Living Tribunal's Realm
The best universe visited in the movie occurs right at the beginning of Strange's tumble through the multiverse. He and America careen past the giant floating heads of who appears to be The Living Tribunal, perhaps the most powerful Marvel cosmic being.
The Living Tribunal first appeared in Marvel Comics in Strange Tales #158 in a key Doctor Strange adventure. A statue of him appears in Loki and he stands to play a major role in the future cosmic dealings of the MCU.
Earth-838
Strange and America crash into Earth-838, which becomes the locus of the movie and the best of all the universes. This universe contains perhaps the most significant cameos in MCU history, including the franchise debuts of the X-Men, Fantastic Four, and Inhumans.
The universe also provides fans with massive clues to the function of the multiverse in the concept of incursions. This idea comes from the 2015 Secret Wars comic book event, a storyline the MCU seems poised to adapt in the near future.