One possible plotline could be Archer and Kiritsugu teaming up to face a powerful common enemy. They might combine their different skills and strategies to overcome challenges.
Perhaps there's a plot where Archer has to learn from Kiritsugu's more ruthless methods. Kiritsugu's no - nonsense approach could make Archer reevaluate his own actions. This could lead to some interesting character development for Archer as he grapples with new ways of thinking.
Another plot could involve a time - travel aspect. Maybe Archer gets sent back in time to meet a younger Kiritsugu. They could then interact in a way that changes the future or has unexpected consequences. For example, Archer might accidentally influence Kiritsugu's decisions in a way that alters the course of events he knows from his own timeline.
Archer is often well - written in these fanfictions. His complex personality and his own set of values can create a lot of interesting interactions, especially when paired with Kiritsugu.
In another scenario, the fanfiction could be set in a post - apocalyptic world. Shirou and the female archer are part of different survivor groups. They meet during a scouting mission. At first, there is tension between them due to the rivalry between their groups. However, as they realize that they share a common love for archery and a desire to rebuild the world, they decide to work together to bring peace and restore the art of archery in the new world.
In some 'itachi meets sarada fanfiction', Itachi could be brought back to life temporarily. He and Sarada might go on a journey together to face a new threat to the village. During this journey, Itachi could act as a mentor to Sarada, teaching her how to handle difficult situations and how to use her Sharingan more effectively.
One possible plotline could be that Harry, perhaps lost in the forest near Forks, stumbles upon Carlisle. Carlisle, being the kind-hearted vampire he is, offers to help Harry. They start to exchange stories about their different worlds, with Harry sharing about the wizarding world and Carlisle about the vampire society. This could lead to an unlikely friendship where they work together to protect both the wizarding and vampire communities from common threats.
A third plotline could be set in an alternate universe where Luke and Leia meet under different circumstances. For example, they could meet as children before they were separated. This would completely change the dynamic of their relationship and lead to a whole new set of adventures and character developments.
One interesting plotline could be Stiles teaming up with the Winchesters to hunt a particularly elusive and dangerous supernatural creature. Maybe it's a new type of werewolf that has powers they've never encountered before.
One interesting plotline could be Luigi and Daisy teaming up to solve a mystery in the Mushroom Kingdom. Maybe there's a strange disappearance of power - ups, and they use their unique skills to figure it out.
One interesting plotline could be their initial meeting being filled with suspicion but gradually turning into mutual respect as they realize they both have a common goal of saving the realm. For example, Jon might be initially wary of Daenerys and her dragons, but as they talk more, they find they can work together against the White Walkers.
One interesting plotline could be Harry somehow traveling back in time to meet Grindelwald in his prime. This could lead to a battle of wits between them, with Harry trying to stop Grindelwald from starting some of his more heinous plans early. Another might be that Grindelwald, seeing Harry's power, tries to recruit him to his side, offering him power and knowledge that Harry has to resist.
Well, perhaps Joey is a big fan of the Batfam in the fanfiction. So when he meets them, he fangirls/fanboys really hard at first. Then, as the story progresses, he gets to know them on a more personal level and discovers that they have their own quirks and insecurities just like regular people, which changes his perspective of them completely.