What are some interesting plot ideas for 'Earth X Arrowverse fanfiction'?

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 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.

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.

A possible plot is centered around the relationships that form during the crossover. Imagine a love story between two characters from different Earths. Maybe a hero from Earth X falls in love with a hero from the main Earth. This relationship could be complicated by the differences in their worlds and the events of the Crisis. Also, a plot about the heroes having to adapt to the different rules and cultures of Earth X would be engaging.

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 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.

Definitely Oliver Queen. His skills as a vigilante and his leadership qualities would make him a great addition. He could be leading the fight against the tyranny on Earth X. Another is Supergirl. Her superpowers would be a huge asset in the battles on Earth X. And of course, Harrison Wells, his intelligence could be used to develop strategies against the Earth X enemies.

Maybe there's a fanfiction where a Sith Lord tries to take over Earth. The Earth's military would be no match for the Sith's powers at first. But then, through some clever thinking and the discovery of a hidden Earth - based energy source similar to the Force, they start to fight back.

For 'a child of earth and sky fanfiction', a plot idea could be centered around the character's discovery of an ancient civilization that was closely tied to the earth and sky. They learn the secrets and wisdom of this civilization which gives them new abilities. They then use these abilities to face a natural disaster that threatens to destroy the balance between the earth and sky. Along the way, they form bonds with other characters who also have a connection to the earth and sky, and together they fight to preserve the world as they know it.