A cool storyline could also be a time - travel or alternate - reality crossover within the fanfiction. Spider - Man and the Avengers could end up in an alternate universe where they have different powers or relationships. They'd have to figure out how to get back to their own reality while also dealing with the threats in this new world, like facing off against evil versions of themselves.
Another storyline might involve Spider - Man bringing in his street - level knowledge to the Avengers. Since he deals with small - time criminals in New York on a daily basis, he could help the Avengers understand the ground - level threats that they sometimes overlook. This could lead to a mission where they have to stop a group of villains who are using the city's infrastructure in a devious plot.
One interesting storyline could be Spider - Man having to use his unique abilities to solve a mystery within the Avengers' headquarters. His agility and spider - sense might lead him to discover a hidden threat that the other Avengers overlooked.
One interesting storyline could be about Spider Man facing a new villain that was created specifically for the fanfiction. This villain might have powers that directly oppose Spider Man's, like the ability to nullify his spider - sense.
One great storyline could be Spider - Man trying to prove himself to the Avengers during the Age of Ultron chaos. He might start off as an underestimated newcomer but then show his true worth by using his unique abilities like his spider - sense to detect Ultron's minions before the others. Another could be a story where Spider - Man has to rescue a captured Avenger from Ultron, using his agility and web - slinging skills to outwit Ultron's defenses.
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.
One interesting storyline could be Spider - Man and Falcon teaming up to stop a new supervillain in the city. This villain might have powers that require both of their unique skills to combat. For example, the villain could be able to fly and shoot energy blasts, so Falcon can take to the air to engage in aerial combat while Spider - Man uses his agility to dodge the blasts on the ground and find a way to disable the villain's power source.
One interesting storyline could be Spider Man and Firestar teaming up to take on a new supervillain in their city. This villain could have powers that force them to use their combined skills in unique ways, like Firestar's ability to fly and create heat blasts along with Spider Man's agility and web - slinging.
One interesting storyline could be Spider Man and Valkyrie teaming up to fight a powerful new villain in New York. Valkyrie's Asgardian powers combined with Spider Man's agility and web - slinging would make for an epic battle. Maybe the villain is a powerful sorcerer who is trying to open a portal to a dark dimension and they have to stop him before it's too late.
One interesting storyline could be Spider - Man and Tigra teaming up to fight a new super - villain in the city. Maybe a villain who can control the minds of animals, and Tigra's connection to her feline side makes her both a target and an important asset in the fight. Another could be a story where Spider - Man has to help Tigra when she gets caught in a scientific experiment gone wrong that starts to change her powers in unexpected ways.
One interesting storyline could be that Spider - Man gets transported to Elsa's world. He could use his web - slinging skills to traverse the icy landscapes. Maybe he helps Elsa control her powers better by showing her how to be more precise with her abilities, like he is with his webs.
There could be a storyline where Spider - Man uses his scientific knowledge to upgrade the Avengers' technology. Or perhaps a story where he has to choose between his loyalty to the Avengers and protecting his own neighborhood. This internal conflict could add depth to the fanfiction. Also, he might team up with Black Widow for a stealth mission where his agility and her skills combine for a successful operation.