Another fanfiction idea could be a prequel to her role in Avengers: Endgame. It could show what she was doing in the cosmos just before she received the call to return to Earth. Maybe she was facing a different threat that was related to Thanos in some way, and this backstory could add more depth to her character in the movie.
One possible fanfiction could involve Spider - Man and Captain Marvel teaming up during the Endgame battle. Maybe Spider - Man uses his agility to distract the enemy while Captain Marvel blasts them with her powerful energy. They could also have some fun banter, like Spider - Man making a joke about how Captain Marvel can fly and he has to swing around.
Imagine in the fanfiction, Spider - Man discovers a new ability during Endgame that can complement Captain Marvel's power. He shares this with her, and they experiment with combining their powers in new ways. For instance, Spider - Man could create a web - like energy field using his new ability, and Captain Marvel could charge it with her cosmic energy to create a powerful shield or weapon against the enemy.
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.
In the fanfic, their relationship might also be a bit of a culture shock. Peter is from Earth, a more down - to - earth kind of hero, while Captain Marvel has been in space and has a different perspective. This could lead to some interesting character development. They might start off not understanding each other but as the story progresses, they learn from one another and become a formidable team in the Endgame - like scenario.
Their dynamic could be really interesting. Peter is often the underdog, still learning about his powers, while Captain Marvel is a fully - fledged powerhouse. So it could be like a novice - veteran relationship, with Peter being in awe of her abilities and Captain Marvel being a bit protective of him.