A brand new trailer for theories on what might be happening in the Loki trailer, some of which concern the strange realities Loki appears to visit. Could some of them be alternate timelines from Marvel Comics?
The comic books are built on endless alternate realities and dimensions, some of which are very well known to comic book readers. They often play a key role in some of the most important stories in the comics, and as such, stand a decent chance of appearing in the Loki series, even if it's just a tantalizing glimpse.
House Of M
One of the most significant alternate timelines of modern Marvel Comics is the world of House Of M. In this alternate reality created by Wanda Maximoff in a moment of desperate grief, she creates a world in which her children Tommy and Billy are still alive. Her father, Magneto, rules the island nation of Genosha, as the head of the House Of Magnus.
None of it is real and leads to tragic consequences for mutants everywhere when Wanda erases all but a handful of mutants from existence with the infamous words "No more mutants." House Of M is one of the Scarlet Witch comics that inspired aspects of WandaVision.
Counter-Earth
A major alternate world from the mid-1990s is that of Counter-Earth. This is a bubble reality that was created by Franklin Richards, the son of Fantastic Four Mr. Fantastic and the Invisible Woman.
Richards placed the Avengers and FF in this reality just as the supervillain Onslaught was about to kill them in one of the biggest crossover events of the decade. The bubble universe was an attempt to reboot and refresh Marvel's legacy characters for new readers but ultimately didn't prove successful. It only lasted a year.
Days Of Futures Past
A lot of alternate timelines in Marvel Comics are associated with the X-Men. That's perhaps because they largely minted the concept in the iconic story Days Of Futures Past. This dystopian future saw mutants hunted down and killed by Sentinels.
Kitty Pryde is sent back in time to try and avert an assassination to change the future. The story, written by Chris Claremont and drawn by John Byrne, was the subject of the 2014 Fox X-Men movie one of the best overall Marvel movies.
The Mojoverse
The Mojoverse is a pocket dimension that exists outside of time and space. The X-Men have had numerous adventures there, usually fighting its grotesque and despotic ruler, Mojo. The surreal and comedic tone of Mojoverse, in which everything is televised, would seem to fit in nicely with the off-kilter vibe of the Loki series.
The Mojoverse first appeared in 1985, in the first issue of the Longshot mini-series by writer Ann Nocenti and artist Art Adams. It played a fairly big role in X-Men Comics in the 80s, including introducing the adorable but weird X-Babies.
Guardians Of The Galaxy 3000
The Guardians Of The Galaxy weren't always the team that fans met in the original 2014 movie. The version of the team with Star-Lord, Rocket, Groot, and others first debuted in the comics in 2008 and were the successors to a team that originally existed in a different timeline.
The original team, including a version of Yondu and Charlie-27, existed in the year 3000. They debuted in 1969. The 31st Century Guardians were later established to be a separate timeline from the main Marvel Universe of Earth-616.
Otherworld
The term Earth-616 comes out of one of the most fascinating bits of Marvel lore. Writer Alan Moore, who co-created the Watchmen with artist Dave Gibbons, created the concept of the Multiverse in Marvel Comics in the form of the Captain Britain Corps and Otherworld. Otherworld is a realm beyond time and space where the figures of Arthurian legend like Merlin continue to exist.
Merlin watches over the entirety of the Multiverse via the corps, which has a Captain Britain in every single universe in existence. Moore first developed the concept in Captain Britan comics specifically for the British audience, and it was later developed by Chris Claremont and Alan Davis in the pages of Excalibur in 1988.
Earth X
Earth X is an alternate timeline in which all people on Earth gain superpowers, rendering the classic Marvel superheroes obsolete. Earth X was a concept by painter Alex Ross and then developed into a 1999 mini-series by writer Jim Krueger with art by John Paul Leon.
The evolution of humanity comes about by the mass release of Terrigen Mists, the source of the Inhumans power (and more recent characters like versions of the Scarlet Witch.
King Thor
An alternate timeline with a lot of potential relevance for the Loki series is that of King Thor. This version of Thor exists thousands of years in the future when he is the grizzled king of Asgard. Thor faces off against Gorr The God Butcher, who is the apparent villain of Thor Love And Thunder.
It would be a nice connection if Loki crossed paths with this timeline, which then may see further development in the movie. King Thor ultimately defeats Gorr and leaves Asgard and Earth behind to fight against the end of the universe.
Age Of Apocalypse
Age Of Apocalypse is one of the best Marvel crossovers from the 90s and also features one of the bleakest comic book timelines.
This alternate timeline comes about when Legion kills Professor X in the past, rewriting history so that Apocalypse decimates the world. The X-Men fight on, led by Magneto, who is in an unexpected romance with Rogue. Everything is flipped upside down, with villains like Sabretooth becoming heroes and heroes like Colossus rendered villainous by the terrible circumstances of this dystopian world.
Year One Thousand
The current Dawn Of X era in X-Men comics began with the shocking revelation that longtime X-Men ally Moira Mactaggart was actually a mutant herself. Not only that, she has lived several lives and is reborn with each death.
In one of her lives, she survived to the Year One Thousand. In this far distant future, mutants and humans alike are nearly extinct, decimated by machines led by Nimrod. This hopeless reality is going to play a major role in the future of X-comics and could be teased in the MCU as well.