One idea could be Thor traveling back in time to prevent Ragnarok from happening in the first place. He could try to change the events that led to Hela's return, like stopping Odin from banishing Loki earlier. Another plot could involve Thor and his friends traveling to different time periods during Ragnarok to gather powerful artifacts to defeat their enemies. For example, they might go back to the time of the ancient Asgardians to find a weapon that can defeat Surtur.
Well, a cool plot might be that Thor travels through time during Ragnarok and ends up in an alternate version of Asgard. In this version, the events of Ragnarok have not occurred yet, but there are different threats. He has to work with the alternate versions of his friends and family to stop this new threat while also finding a way to get back to his own time and save his Asgard. It could involve some really interesting character interactions and battles.
One interesting plot idea could be the exploration of Asgardian characters' reactions to Thor's journey in Ragnarok from a different perspective. For example, how the common Asgardians felt about Thor's battles and his newfound friends. Maybe some of them were skeptical at first but then became inspired by his growth.
One character that could be added is the Enchantress. She could use her magic to either help or hinder Thor's time - travel attempts. Another could be Beta Ray Bill. He could team up with Thor in the different time periods they visit during their time - travel adventures. And perhaps the Warriors Three could be brought back through time - travel shenanigans, even if they died in the original Ragnarok storyline.
A cool plot could be that Thor and Tony have a bit of a rivalry at first. Thor thinks Tony is too full of himself with his high - tech gadgets, and Tony thinks Thor is just a brute with a hammer. But then they are forced to work together when an alien threat arrives that is immune to Tony's tech and Thor's brute force alone. As they get to know each other better, they learn to combine their strengths and defeat the enemy. They might even become good friends in the end.
One idea could be exploring Jane's further adventures on Earth while Thor is away in Asgard. Maybe she discovers some new scientific phenomena related to the Aether that was in her. Another could be Thor taking Jane to a secret part of Asgard that no human has ever seen before, and they face some challenges there together. Also, a plot where Jane gets kidnapped by an enemy of Thor's and Thor has to rescue her, but during the rescue he discovers some new powers within himself.
One plot idea could be Thor landing in the Viking era and being mistaken for a god. The Vikings might try to either worship or challenge him. Another could be a Viking warrior being chosen by Thor to help him on a quest in Asgard. Or perhaps Thor has to team up with a group of Vikings to fight a common enemy like a giant frost monster.
A plot could involve a magical rift that transports Thor to Wonder Woman's world. He doesn't understand the ways there at first and causes some chaos. Wonder Woman has to step in to keep the peace and teach him about her world. In the process, they discover a threat that is targeting both their realms and must combine their powers to defeat it. For example, Thor's lightning and Wonder Woman's lasso could be used in a unique way to counter the enemy's magic.
A possible plot could be that Thor discovers Tony's love for food and tries to court him through cooking Asgardian delicacies for him. Since Tony is always busy in his lab, Thor could also offer to help him with his projects in his own Thor - like way, which might initially cause some chaos but eventually lead to them getting closer. Or perhaps Thor and Tony are forced to go on a mission together where they are stranded in a strange place. In this difficult situation, they rely on each other and Thor starts to court Tony more seriously.
One plot idea could be Thor and Loki as younglings getting into mischief in Asgard's forbidden areas. Maybe they accidentally unleash a minor magical creature that causes chaos in the palace. Another could be a story where they compete in a friendly, yet intense, training tournament to prove who is the better warrior at a young age. And they could also go on a secret adventure outside of Asgard, defying Odin's rules, to explore a rumored enchanted forest.
One plot idea could be that Hermione, through some magical accident, ends up in the Asgardian realm. Thor then has to help her get back home while she uses her magic to solve various problems in Asgard, like dealing with a mysterious magical threat that the Asgardians' magic can't handle.
One idea could be Yoda traveling back in time to train Anakin Skywalker differently, thus preventing his fall to the dark side. Maybe he goes back to the very beginning of the Jedi Order to gain more knowledge about the Force and bring it back to his own time.