Perhaps Xander is kidnapped by Spike because Spike has been cursed or influenced by some dark magic. In this case, he may not be fully in control of his actions. And as the story progresses, Xander could try to find a way to break the spell on Spike while also trying to escape. Another plot could be that a third party hires Spike to kidnap Xander, and Spike reluctantly agrees for some personal gain, like money or a way to get rid of his own enemies. Then Xander and Spike might end up having to work together to face the real threat behind the kidnapping.
Yes, there might be. You can start by looking on popular fanfiction platforms like Archive of Our Own or FanFiction.net. Just search for 'Xander Spike kidnapped' in their search bars and see what comes up.
It could be that Spike is kidnapped by a new, unknown threat from outside of Equestria. This new enemy might see Spike as a key to unlocking some sort of powerful magic in Equestria. Pinkie Pie could use her intuition to find out where Spike is, while Rarity might use her connections to get information on this new enemy.
One possible plot could be that Jack is kidnapped by an enemy from his past who has a vendetta against him. The kidnapper might be seeking revenge for something Jack did long ago. Another plot could be that Jack is kidnapped because he has some valuable information that the kidnappers want.
Buffy would probably be involved. Since she's the slayer and Xander is her friend, she'd be on a mission to rescue him from Spike. Willow could also be in it. As Xander's best friend and a powerful witch, she'd use her magic to try and find Xander or fight against Spike. And Giles, too. He'd be the one providing knowledge and guidance on how to deal with a vampire like Spike who has kidnapped Xander.
One common theme is the exploration of their unlikely connection. Since they are so different in the original context, fanfiction often focuses on how they bridge that gap.
In this fanfiction, Catwoman might kidnap a detective who has been getting too close to uncovering her identity. She could hold the detective hostage in an elaborate hideout. As she holds the detective, she might have some internal struggle about whether to harm the detective or let them go. Another idea is that she kidnaps a famous fashion designer to get her hands on the latest high - tech fashion items that could give her an edge in her cat - burglar activities.
One possible plot could be that Shawn is kidnapped by a group who mistakes him for someone else. They hold him hostage in an abandoned building while his friends race against time to find him. Another plot might involve Shawn being kidnapped as part of a revenge scheme against someone close to him. The kidnappers then demand some form of restitution in order to release him.
One possible plot could be that Tails is kidnapped by an old enemy seeking revenge. Maybe Eggman wants to use Tails' intelligence for his own evil schemes. He could hold Tails captive in his secret lair and try to force him to build some powerful weapon.
A Tenten kidnapped fanfiction could take a really interesting turn if she's kidnapped by an unknown organization that is actually experimenting on ninjas to create super - soldiers. Tenten, with her strong will and skills, becomes a key subject. Her friends suspect foul play when she doesn't return from a routine mission. As they search for her, they discover clues that lead them to this secret organization. The fanfiction could explore themes of friendship, perseverance, and the fight against unethical experimentation.
Maybe Pinkie Pie is kidnapped by a group who wants to use her party - planning skills for their own evil purposes. Her friends, like Twilight Sparkle using her magic and Rainbow Dash her speed, try to track her down. They might also discover some secrets about Pinkie Pie's past during the rescue mission.