A more complex Arrowverse crossover fanfiction idea could involve time travel. What if a character from 'Legends of Tomorrow' accidentally alters the timeline in a way that affects all the other Arrowverse shows? This could bring characters together in unexpected ways as they try to fix the timeline. They might have to face versions of themselves from different timelines, creating a lot of drama and action.
Another interesting angle for Arrowverse crossover fanfiction is exploring the relationships between characters from different shows. Maybe a story where Cisco Ramon from 'The Flash' visits Star City and teams up with Felicity Smoak from 'Arrow'. They could share their tech knowledge and have some humorous exchanges while working on a mission together.
One idea could be a story where characters from different Arrowverse shows team up to fight a new, powerful villain from a different dimension. For example, Oliver Queen from 'Arrow', Barry Allen from 'The Flash', and Kara Danvers from 'Supergirl' could combine their skills and powers to take on this threat.
Maybe the Flash could visit the MCU. He could race against Quicksilver. It would be a really cool showdown of speedsters from different universes. And then the Flash could get involved in an MCU - level threat, like Thanos' invasion but in a different timeline. He could use his speed to try and steal the Infinity Gauntlet from Thanos, creating a whole new plotline for a fanfiction.
A cool concept could be a crossover where the technology in Gotham and the magic in Star City somehow get mixed up. Batwoman, being more used to high - tech gadgets, and Arrow, who has some experience with magic - related threats, have to combine their skills to set things right. For example, a device that was supposed to enhance Batwoman's suit ends up being enchanted by magic from Star City, and they need to figure out how to fix it and stop the villain who caused the mix - up.
One idea could be that the Winchesters end up in Star City and team up with the Arrow to fight a demon that is using technology to cause chaos. Maybe the demon has possessed some of the tech - savvy villains in the Arrowverse.
One idea could be a crossover where characters from Arrowverse and Young Justice have to team up to stop a multiverse - threatening villain. For example, Green Arrow and Nightwing leading the combined forces.
One idea could be a crossover of characters from different Arrowverse shows on Earth X. For example, having Barry Allen from 'The Flash' team up with Kara Danvers from 'Supergirl' to fight against the evil regime on Earth X. They could use their super - speed and super - strength respectively to take on the powerful foes there.
One idea could be that the Flash from Arrowverse accidentally runs into a different dimension where he meets the Justice League. He then has to team up with them to stop a powerful villain that is threatening both his world and the Justice League's world.
One interesting crossover could be the Flash from Arrowverse meeting Quicksilver from the Avengers. They could have a race to see who is truly the fastest. Another could be Green Arrow teaming up with Hawkeye for an archery - based mission where they share their different techniques and arrow - making skills.
One interesting concept could be the different team - ups. For example, Batman might team up with Green Arrow in unique ways that we don't see in the regular DC universe. Maybe they combine their detective skills to solve a complex mystery that spans across both Gotham and Star City.
One interesting Arrowverse OC fanfiction could be about an OC who has the power to manipulate time and how they interact with the existing heroes and villains in the Arrowverse. They might start by trying to prevent a major disaster that was foreseen in a vision.
One key element is the character interactions. Seeing characters like Clark Kent and Oliver Queen interact, given their different backgrounds and powers, is really exciting. Another element is the merging of storylines. For example, how the threats in Smallville might be related to those in the Arrowverse.