In a 'Team Flash meets Supergirl' fanfiction, there could be an epic team - up. The Flash might use his super speed to save Supergirl from a kryptonite - powered trap. Then they could join forces to fight a common enemy like Lex Luthor or an alien invasion. The scientific minds in Team Flash could also help Supergirl understand some new aspects of her powers.
Supergirl would be really interesting. Her alien origin and her super strength, along with her ability to fly, would make her stand out. She could bring a new dynamic to Team Flash with her different set of powers and her more idealistic view of heroism, which might contrast with some of the more street - level concerns of Team Flash.
In a 'Supergirl meets the Flash fanfiction', they might team up to fight a powerful common enemy. For example, a super - villain who can manipulate time and space, and only their combined powers can stop him.
Lex Luthor could be a great main antagonist. He could be jealous of their combined power and see them as a threat to his plans of world domination. He might create some high - tech weapons specifically designed to counter their abilities.
Perhaps an interdimensional villain. This villain could be causing disruptions in both The Flash's and Supergirl's dimensions, forcing them to meet and join forces to stop it. The villain could have powers that are a challenge for both of their unique abilities.
One popular storyline is where Flash and Supergirl team up to fight a common, powerful enemy like a super - villain from another dimension. They combine their speed and strength in unique ways to save the world. Another is a more character - driven plot where they develop a romantic relationship. Flash's quick - witted charm and Supergirl's strong - willed nature make for an interesting dynamic. There are also storylines where they swap powers temporarily, leading to humorous and action - packed situations as they learn to use each other's abilities.
In this fanfiction, The Flash and Supergirl could start off as rivals. They both think their way of protecting people is the best. But as they face a common enemy that is too strong for either of them alone, they learn to work together and respect each other's abilities.
A great storyline could be about a mystery that spans both their cities. They start investigating separately but soon realize they need each other's help. Team Arrow has the skills to infiltrate dangerous locations, while Team Flash can quickly travel between the two cities to gather information. There could also be a storyline where a powerful and ancient artifact is discovered, and both teams want to keep it safe from falling into the wrong hands. They would need to overcome their differences in approach to protect the artifact and the world from its potential misuse.
In fanfiction, when Team Flash meets Team Arrow, there could be an exchange of superpowers knowledge. The Flash's speedster abilities might amaze the members of Team Arrow, while the archery and combat skills of Team Arrow could be something new for Team Flash to learn from. Maybe they would team up to fight a common and extremely powerful villain that neither team could handle alone.
One interesting crossover could be the characters teaming up to fight a common supervillain. For example, Lex Luthor from Supergirl's world could team up with some of Arrow's villains like Deathstroke, and Team Arrow and Supergirl would have to combine their skills to take them down.