Maybe in the fanfiction, Spiderman and Miles Morales meet in an alternate dimension where their powers work differently. They have to learn about each other's abilities all over again and combine their skills to find a way back to their own dimensions. This would allow for a lot of character development and exploration of their powers.
One idea could be that they have to team up to stop a new villain who has the ability to manipulate time. This would create a lot of interesting scenarios as they try to figure out how to defeat the villain while dealing with the chaos of a disrupted timeline.
A cool plot could be that there is a powerful artifact that has been stolen and both Spiderman and Miles Morales are after it. However, they initially suspect each other of being the thief. As they start to investigate, they realize they've been set up and must work together to retrieve the artifact and take down the real bad guys. This would create some great tension and then a strong bond between the two characters.
The Green Goblin could be a great main antagonist. He could be causing chaos in both Spiderman and Miles Morales' neighborhoods, and they have to put aside any differences to stop him. His maniacal nature and powerful weapons would pose a great threat to both heroes.
One idea could be that Naruko, with her ninja skills, and Miles Morales, with his spider - abilities, team up to fight a common enemy in a dimension - hopping adventure. Maybe a villain is stealing energy from different universes and they have to use their unique powers to stop it.
One idea could be that Spider Gwen and Miles Morales have to team up to stop a new villain who has the ability to manipulate time. This would put their relationship to the test as they struggle to work together while also dealing with the chaos of the altered timelines. Another plot could involve them traveling to an alternate dimension where their roles are reversed, and they have to learn to adapt to each other's usual situations. A third idea is that they discover a long - lost relative who has superpowers and they must decide whether to trust this new person or suspect them of having ulterior motives.
One idea could be that Miles and Gwen team up to stop a new villain who can manipulate time. They have to race against the clock to figure out the villain's weakness before the city is frozen in a time loop. Another could be that they discover a parallel dimension where they are the only superheroes left and have to find a way to restore their respective universes.
A plot could involve Spiderman getting framed for a crime in Daredevil's territory. Daredevil initially suspects Spiderman but as he investigates, he realizes that there's a bigger conspiracy at play. They then join forces to clear Spiderman's name and expose the real culprits. This would involve a lot of detective work from Daredevil and Spiderman using his agility to gather evidence.
Perhaps there's a situation where a powerful criminal organization has a device that can scramble Daredevil's senses and Spiderman's spider - sense. They have to rely on each other's instincts and skills that don't involve their heightened senses to stop the bad guys from using the device for more malicious purposes.
One idea could be that they team up to take on a new supervillain in town who has the ability to manipulate time. This would create a lot of chaos and require their combined skills to stop. Another could be a comical misunderstanding where Deadpool thinks Spiderman has stolen his favorite weapon and they have a fight before realizing it was all a mistake.
One idea could be that different versions of Spiderman from across the multiverse team up to fight a common enemy that can travel between dimensions and is threatening all their worlds. For example, a powerful symbiote - like creature that has the ability to absorb the powers of each Spiderman it defeats.
One idea could be that Spiderman 2099 has to team up with a group of rebels from a future dystopia to take down a powerful corporation that controls the city. They might face advanced technology and dangerous enforcers.
In this fanfiction, the female Spiderman could be a huge fan of the original Spiderman. She has been following his adventures from afar. One day, she gets the chance to meet him. However, at the same time, a powerful criminal organization discovers their identities and tries to capture them both. So they have to work together to not only escape but also take down this organization that is causing harm to the city.