The OC could be a villain at first, with powers similar to Pietro's speed but using them for evil. Pietro has to convince the OC to change their ways. This could involve a lot of action - packed chases and intense conversations as Pietro tries to reach the good side of the OC.
One idea could be an OC who has the power to manipulate time like Pietro. They could team up with Pietro to save the Avengers from a time - trapped enemy. The OC might be from a different dimension where time works differently, adding an interesting dynamic.
The OC could be a mutant from a different country who comes to the X - Men school. Pietro is immediately intrigued by her different culture and way of using her powers. They start to exchange stories about their mutant experiences, and a relationship forms based on mutual understanding and respect for their differences.
One plot idea could be an Avenger taking in an OC (original character) who has unique powers but is scared to use them. The Avenger, like Thor, could teach the OC about courage and how to control their powers. Another idea is an OC who is a tech genius and gets adopted by Tony Stark. They work together on new Iron Man suit designs. A third idea is an OC with a dark past being taken in by Black Widow. She helps the OC face their demons.
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.
One idea could be creating an OC who has a unique power related to time manipulation. They could be from a different dimension and end up in the Avengers' world. Another idea is an OC who is a master of ancient magic and teams up with Doctor Strange within the Avengers group. Maybe an OC that is a super - intelligent android created by a villain but has a change of heart and joins the Avengers.
An interesting plot could involve an OC who has the power to communicate with animals. In the story, they use this power to gather intel on the villains' plans. The animals could provide information that the Avengers wouldn't be able to get otherwise, like the location of a hidden lair or the movements of enemy troops.
One idea could be an evil OC who has the power to manipulate time and uses it to disrupt the Avengers' plans at crucial moments. For example, going back in time to prevent key events that led to the Avengers' formation.
Another interesting concept is an OC who is a scientist researching Venom's origin. They accidentally get infected and use their new powers to help the Avengers in a unique way. For example, they could have enhanced senses that allow them to detect threats before the Avengers even know they're there. They also have to struggle with the dark side of the Venom symbiote while trying to be a hero.
One plot idea could be Pietro and Wanda exploring their powers further in a world that fears them. They might have to team up with other X - Men to face a new, powerful mutant - hating organization. Another could be a story set in an alternate universe where they have different relationships with the other mutants. For example, Pietro could be more of a loner and Wanda has to convince him to work with the team.
One plot idea could be that the female OC supersoldier is sent on a mission to retrieve a powerful artifact before the bad guys get it. Along the way, she has to team up with some of the Avengers she doesn't trust at first. Another idea is that she discovers a dark secret about the supersoldier program she was part of that has ties to an enemy of the Avengers. Or she could be framed for a crime she didn't commit, and the Avengers have to decide whether to believe her or not while she tries to clear her name.
One plot idea could be that the male OC is a new recruit to the Avengers. He initially clashes with Captain America due to different combat styles. But as they face various threats together, they gradually learn from each other and form a deep friendship. The OC could have a special power that is crucial in a particular mission, and Captain America comes to respect his abilities.