One idea could be a crossover with the X - Men. Spider - Man could team up with Wolverine. Their different fighting styles would make for some amazing action scenes. Wolverine's brute strength and healing factor combined with Spider - Man's agility and web - slinging abilities would be a great combination.
Another option is a crossover with Daredevil. Since they both operate in New York City, they could cross paths while fighting crime. Their different senses - Spider - Man's spider - sense and Daredevil's enhanced hearing and other senses - could lead to some interesting interactions as they work together to take down the bad guys.
A crossover with Captain America could be great too. Spider - Man, with his youth and modern - day sensibilities, could learn a lot from Cap's old - fashioned values. They could fight side by side against Hydra agents or other villains, and Spider - Man could show Cap some new tricks when it comes to acrobatics in combat.
There could be a situation where a Transformer's technology gets mixed with Oscorp's experiments. This creates a new kind of threat that Spider - Man has to face. The Transformers get involved because it's their technology that's been misused. Together, they figure out a way to reverse the effects and defeat the new hybrid - like villains.
One idea could be that during a mission crossover, Spider - Man gets injured while trying to protect a civilian from an unexpected attack by a powerful enemy. Maybe he takes a hit meant for an Avenger and his suit's technology malfunctions, leaving him vulnerable.
In a Harry Potter and Spider - Man crossover fanfiction, perhaps the Venom symbiote attaches itself to a Hogwarts student. Spider - Man then has to travel to the wizarding world to stop the now - corrupted student from causing chaos. Along the way, he discovers that the magic in the wizarding world can both help and hinder his attempts to subdue the symbiote - controlled student. Harry and his friends might initially be suspicious of Spider - Man but then realize they need his unique skills.
One idea could be to have the Ninja Steel Rangers cross over with the original Mighty Morphin Power Rangers. They could team up to fight a common enemy that is too powerful for either team alone. Maybe Lord Zedd and Galvanax form an alliance, forcing the two ranger teams to combine their powers and zords in new and creative ways.
One idea could be exploring a different origin story for Spider - Man in the fanfiction. Maybe he gets his powers from a scientific experiment gone wrong in a completely new way. For example, instead of being bitten by a radioactive spider, he could be exposed to a mutagenic serum that gives him spider - like abilities along with some unique side - effects that he has to deal with.
Well, they could be in a situation where Iron Man's reputation is on the line due to some false accusations. Spider - Man believes in his innocence and decides to help him clear his name. Together, they start investigating who is behind the smear campaign. Along the way, they encounter a powerful enemy who is trying to keep them from finding the truth. This would involve a lot of detective work from Spider - Man and high - tech solutions from Iron Man.
One idea could be a crossover with the X - Men. Spider - Man could find himself in the middle of a battle between the X - Men and some common enemy, like the Sinister Six. He'd have to figure out how to work with mutants, which is a whole new experience for him. Another idea is a crossover with the Fantastic Four. Maybe Spider - Man gets caught up in one of their space - related adventures. Reed Richards could be fascinated by his web - shooters and try to study them, while Spider - Man would be in awe of their super - scientific gadgets.
Another interesting plot could be that a mad scientist creates a device that can separate Venom from his host. However, the separation goes wrong and the symbiote energy starts to spread across the city, infecting people. Spider - Man and Venom must work together to find a way to contain the energy and save the city.
A crossover with the Avengers is also great. Picture Spider - Man having to prove himself to the more established heroes like Iron Man and Captain America. He could bring his unique street - level hero skills to a big - scale Avengers mission.