One common theme is self - discovery. Peter often has to re - evaluate who he is when he sees different versions of himself in alternate dimensions. For example, he might see a version of himself that is more ruthless or more vulnerable, which makes him think about his own values.
One interesting one could be 'Peter Parker's Multiverse Adventure'. In this fanfic, Peter Parker gets accidentally pulled into an alternate dimension where he meets different versions of himself. It's full of action and self - discovery as he has to figure out how to get back to his own dimension while dealing with the new challenges and powers of his alternate selves.
There might be a group of interdimensional hunters. They target beings who cross into alternate dimensions without permission. Peter, being an unexpected visitor in this new dimension, becomes their target. They are highly skilled and have advanced technology or magic that makes them difficult to defeat. They believe that Peter's presence could disrupt the balance of the alternate dimension.
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 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.
A really unique concept is when Peter's consciousness gets split among different dimensions. So he has to find a way to reunite his consciousness while also dealing with the different situations in each dimension. For example, in one dimension he might be a wanted criminal, while in another he's a hero worshiped by all. This creates a lot of internal conflict for Peter as he tries to piece himself back together.
One idea could be that Peter discovers he has superpowers unique to this alternate dimension. For example, he might be able to control time in a different way than in his own world. Another plot could involve Peter meeting alternate versions of his friends and family, and having to deal with the differences in their personalities and relationships. Maybe in this dimension, his best friend is his enemy, and he has to figure out how to change that.
Maybe Thor. Peter has never seen someone as powerful as Thor with his hammer and god - like abilities. Thor's larger - than - life presence could be really fascinating for Peter.
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.
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.