What are some interesting plot ideas for Avengers Endgame crossover fanfiction?

A really cool plot idea could be that the Avengers are watching Endgame in a sort of 'alternate reality cinema' where the events in the movie start to bleed into their real world. So they have to stop the movie from fully playing out to prevent chaos in their own universe. This would involve a lot of action and strategic thinking as they try to stop things like Thanos from emerging from the screen while also trying to understand the significance of what they're seeing in the movie.

Perhaps a fanfiction where the Infinity Stones in the Endgame have an unexpected effect on certain anime characters. These characters start to develop new abilities or forms that are a blend of their anime selves and the power of the Stones. This could lead to a whole new dynamic in the fight against Thanos, as the Avengers have to figure out how to work with these newly - empowered anime allies.

One idea could be an OC who has the power to time - travel in a unique way, not like the Avengers' method. They could accidentally disrupt the events of 'Endgame' further while trying to help. For example, they might create alternate timelines where different villains gain power. Another plot could involve an OC who is a long - lost relative of one of the Avengers. They show up during the final battle and use their hidden powers to turn the tide. And a third idea is an OC who is from a different dimension entirely and has knowledge of how to defeat Thanos more easily, but they have to convince the Avengers to trust them first.

Well, in some fanfictions, the time travel might go wrong in a way that it starts to merge different timelines. So the Avengers not only have to deal with Thanos but also with the chaos of colliding timelines. For example, characters from different points in time start interacting in strange ways, like an older version of Iron Man meeting his younger self. This can lead to a lot of interesting character development and conflict resolution.

One idea could be exploring Red Skull's redemption arc. Maybe in the fanfiction, he somehow manages to break free from his eternal punishment on Vormir and joins the Avengers in the final battle against Thanos. He could use his knowledge of the Soul Stone and the other Infinity Stones to help the Avengers turn the tide.

One idea could be a crossover between 'Endgame' and a fantasy world like 'Lord of the Rings'. Imagine the Avengers having to fight Sauron's forces in Middle - earth. Another could be a crossover with 'Star Wars', where the Avengers team up with the Jedi to battle a new threat that spans across galaxies.

In some 'Avengers Endgame Fix It Fanfiction', there might be a concept of time travel without the glitches that occurred in the movie. Maybe they could have a more stable time - travel device which allows them to not only reverse the snap but also fix other events that led to Thanos' victory. This could involve changing things like Loki's escape with the Tesseract in a more beneficial way for the Avengers.

A post - Avengers Endgame fanfiction could center around the psychological impact on the survivors. Like Natasha's death still haunts the team. How does Steve Rogers' decision to go back in time and live his life with Peggy affect the others? It could also be about the search for new Infinity Stones. What if there are more Stones out there? And another idea is to write about the Avengers mentoring a new team of young heroes, passing on their skills and knowledge in a post - Endgame setting.

In a rewrite fanfiction, perhaps Loki could have faked his death all along. He could then return during the events of Endgame, bringing with him an army of Asgardians he had secretly been gathering. His cunning and strategic mind could add a whole new layer to the battle plans against Thanos and his forces.

Imagine a fanfiction where Captain Marvel uses her energy - based powers in a completely new way during the final battle in Avengers: Endgame. Instead of just punching and flying around, she could manipulate the energy fields in a way that disrupts Thanos's entire army. This would be a creative take on her character and her abilities.