One great fanfiction in this category could be 'The Convergence of Universes'. It explores how MCU characters interact with Earth - 616 Peter Parker in a really exciting way. The story has some great action scenes where Peter shows off his skills from Earth - 616 while also learning from the MCU counterparts.
I really like a fanfic called 'Cross - Dimensional Allies'. In it, MCU meets Earth - 616 Peter Parker and they have to team up to face a common threat. It's interesting to see how the different versions of the characters mesh together. Peter from Earth - 616 has a different set of experiences and abilities compared to the MCU version, and this creates a lot of tension and drama in the story.
The different power - sets and how they interact. Earth - 616 Peter might have different abilities or a different way of using his powers compared to the MCU version. For example, his web - shooters might work differently or he could have some additional powers that the MCU Peter doesn't. This can create cool fight scenes and problem - solving situations in the fanfiction.
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.
MJ is an obvious choice. She has a connection with Peter in the MCU already. Then there could be Gwen Stacy, who is a classic love interest in the Spider - Man lore. Another potential character could be Black Cat. Her flirtatious nature would add an interesting dynamic to the harem.
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.
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.
One interesting storyline could be Peter Parker trying to balance his superhero duties with his relationships in the harem. For example, he has to keep his identity a secret from some of the girls while still being there for them. Another could be the different dynamics between the characters in the harem, like a love - hate relationship with one of them.
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.
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.
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.