There could also be new characters created specifically for the fanfiction. Maybe a new love interest for one of the Peters, or a sidekick that is unique to this particular fan - made story. This new character could bring a fresh dynamic to the relationship between the two Peters.
In some fanfictions, they might team up to fight a new villain. Picture them combining their powers and skills. Peter Parker's acrobatic skills and spider - sense along with the other Peter's unique abilities could make for an epic showdown against a powerful enemy.
You can try searching on popular fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. They have a large collection of fanfictions, and by using the relevant search terms, you might be able to find the 'Peter meets other Peter fanfiction' you're looking for.
A plot could involve two Peters from parallel universes. They initially clash because they have different personalities or ways of doing things. For example, one Peter might be more introverted and scientific, while the other is more outgoing and action - oriented. But as they get to know each other, they start to work together to solve a common problem that threatens both of their universes. This could include fighting a super - villain who has found a way to cross between the universes. Another aspect could be that they discover some hidden secrets about their own identities or powers through their encounter with the other Peter.
One possible plot could be that Peter Parker, while on a school trip or some scientific research in space (maybe with Stark tech), accidentally stumbles upon Peter Quill and the Guardians of the Galaxy. They initially have a bit of a misunderstanding as their ways of doing things are quite different. Parker is used to the more down - to - earth (literally) problems in New York, while Quill is dealing with intergalactic threats. But they soon realize they can learn from each other. Parker could teach Quill about the latest Earth - based technology, and Quill could show Parker the wonders of the galaxy.
Maybe in the fanfiction, MCU Peter is on a mission when he accidentally stumbles into a portal and ends up in the world of another Peter. They start comparing their lives, like how different their love interests are. MCU Peter could learn some old - school web - slinging techniques from the other Peter, and they end up having to fight a villain that threatens both of their worlds, leading to a great team - up.
Doc Ock could also be a likely villain. He is intelligent and has those powerful mechanical arms. Imagine the two Peters trying to figure out how to stop his arms from causing destruction. MCU Peter might use his Stark - tech knowledge, while the other Peter could use his more traditional problem - solving skills to take on Doc Ock.
Peter Parker is a science - minded individual, always looking for ways to use his intellect to solve problems. Peter Quill, while not lacking in intelligence, is more about gut instincts and his ability to improvise in dangerous situations. This difference could cause some friction at first. But when it comes to protecting others, their personalities would mesh. Parker's selfless nature to protect the people of New York and Quill's determination to keep his crew and the galaxy safe would bring them together. They could learn from each other's approaches to handling difficult situations.
One possible scenario could be that Loki, in his mischievous ways, decides to play a prank on Peter Parker. Maybe he disguises himself as a normal citizen and lures Peter into a situation where he has to use his spider - sense and quick thinking to figure out Loki's true identity. This could lead to an interesting battle of wits between the two, with Loki's magic against Peter's acrobatic and web - slinging skills.
There might be new witches and wizards who have heard of his story. They could be either fascinated or disgusted by his past deeds. He may also run into future versions of Hogwarts professors. They would probably be very different from the ones he knew, with new teaching methods and different personalities.