Well, perhaps a plotline could involve the Arrow teaching some of the Avengers his unique combat techniques. For example, showing Hawkeye some new archery tricks. And in return, the Avengers introduce him to their advanced technology for upgrading his arrows.
A possible plotline is that the Arrow gets involved in an Avengers - level threat that his city couldn't handle alone. He has to adapt to the Avengers' way of working, which is on a much larger scale. There could be conflicts at first as he tries to fit in, but eventually, they all work together to save the world.
The Arrow is sure to be a main character. In addition, Hawkeye would be a crucial character in this fanfiction. Since they both are archers, there could be a lot of interaction between them, like competing or collaborating in archery - related tasks. And of course, Captain America with his leadership skills would also be among the main characters to lead the team that now includes the Arrow.
One interesting plotline could be the Flash and Arrow teaming up to face a common enemy that has powers beyond their usual foes. For example, a meta - human with the ability to manipulate time, which forces them to use their combined skills of speed and archery in creative ways.
In such fanfiction, a common plotline is that Harry's decision to join Voldemort creates a power shift. He might use his status as the 'Boy Who Lived' to undermine Dumbledore's reputation further. Since many in the wizarding world had put their faith in Harry, his joining Voldemort could lead to widespread panic and confusion. Harry could also start to recruit other disillusioned wizards to Voldemort's cause, using his own charm and the false narrative that Voldemort is actually a liberator of the wizarding world from the old, restrictive ways.
One possible plotline could be Naruto being transported to the Arrow universe and attracting the attention of various female characters. Maybe he uses his ninja skills to help them in their battles against villains in Star City, and in the process, romantic interests start to develop.
One possible plotline could be that Felicity discovers she's pregnant just as a major new threat emerges in Star City. This creates a dilemma for her as she wants to help the team but also protect her unborn child.
One interesting Arrow fanfiction could be about Oliver Queen having to face an enemy from a parallel universe. This would bring in new and exciting elements to the story as he has to adapt to different fighting styles and powers.
One possible plotline could be that the 'darhkness' is a new super - villain or an ancient evil that has been awakened. The Arrow team has to find a way to defeat it using their skills and newfound powers or technology.
One interesting Avenger lice fanfiction could be about how the Avengers deal with a lice outbreak in the compound. Maybe they use their super - powers in unexpected ways to get rid of the lice. For example, Thor could use his lightning to zap the lice away.
There could be a fanfiction where the entire Avenger cast gets transported into an alternate universe where they have to act as their characters in real - life situations. So, Robert Downey Jr. as Iron Man has to actually build his suit and save the day in a world that's a mix of the real world and the Marvel universe.
One interesting Avenger Bolsheviks fanfiction could be about the Avengers adapting Bolshevik ideals in a post - apocalyptic world. They might use the principles of equality and shared resources from Bolshevism to rebuild society.