Another development could be that the dragon actually needs Hiccup's help. Maybe the dragon is injured or has a problem in its lair that only a human can solve. So, instead of harming Hiccup, it keeps him captive until he can fix the issue. This could lead to a very interesting relationship between them.
Well, one plot development could be that Hiccup uses his wits to escape. He might study the dragon's behavior while captive and find a weakness to exploit. For example, if the dragon has a particular routine when it leaves the lair to hunt, Hiccup could use that time to make his escape.
One possibility is that Naruto's friends launch a rescue mission. They would use their unique skills, like Sasuke's Sharingan or Sakura's medical ninjutsu combined with her combat skills, to find and save Naruto.
One possible plot development could be that his friends immediately launch a rescue mission. They might use their unique skills and resources to track down the kidnappers. For example, if Obi - Wan is involved, he could use his Jedi mind tricks to interrogate possible informants in the underworld.
In this fanfiction, perhaps Harry is kidnapped by the Order because they think he's being influenced by dark forces. As the story unfolds, he could start to understand their reasons while also uncovering a traitor within the Order who wants to harm him for real. Or, he might use his skills to turn the situation around and make the Order see that they were wrong to kidnap him in the first place. He could then lead them in a new direction against Voldemort.
Well, one possible plot development could be that the kidnappers demand a ransom from Batman. Batman then has to race against time to find Robin without alerting the media or causing panic in Gotham. Another development might be that Robin manages to leave some hidden clues for Batman to find while being held captive. Maybe he uses his martial arts skills to briefly overpower one of the kidnappers and mark a symbol on the wall that only Batman would understand.
Well, one possible plot development could be that his friends start a rescue mission right away. They might use magic to track the vampire's lair. For example, Hermione could use her extensive knowledge of spells to create a tracking charm. Another development could be that Harry discovers some hidden power within himself while being held captive, something that he can use to either escape or fight the vampire when the time comes. Maybe he has some latent ability related to his connection with Voldemort that can be used against the vampire's dark magic.
One possible plot development could be that Naruto's friends in Konoha realize he's missing and start a search mission. They might suspect Kumo immediately due to the history of tensions between the two villages. Meanwhile, in Kumo, Naruto could be held in a secret location. Some in Kumo might want to use him as a bargaining chip against Konoha, while others might see his potential and try to turn him into an asset for Kumo.
One possible plot development could be that Duke's friends in the Bat - family immediately start a search operation. They might use their various skills and resources to track down the kidnappers. For example, Batman could analyze the crime scene for any clues while Robin tries to hack into security cameras in the area.
In this fanfiction scenario, Naruto's unique abilities like his shadow clones and rasengan would be interesting to see in the context of being kidnapped by Rias Peerage. Maybe the Peerage kidnapped him because they saw his power and wanted to use it for their own purposes. Naruto might resist and start training in secret to get stronger and break free. He could also form an alliance with other characters who oppose Rias Peerage in their world.
One possible plot development could be that the guild members quickly realize Lucy is missing and start a search. Natsu, being her closest friend, might lead the charge. They could follow any clues left behind, like a piece of Lucy's clothing or a strange magical residue. Another development could be that the kidnappers demand a ransom from the guild in the form of a powerful magical item. The guild then has to decide whether to give in or find another way to rescue Lucy. Or perhaps Lucy manages to escape on her own using her Celestial Spirit powers. She could call upon one of her spirits, like Leo, to help her break free from her bonds and then find her way back to the guild while avoiding the kidnappers.
Well, it could be that Kate has some ulterior motives for kidnapping Stiles other than just causing trouble for the pack. Maybe she thinks Stiles has some knowledge about a powerful supernatural artifact or a secret that could help her in her own goals. As the story progresses, Stiles could start to form a strange sort of bond with Kate, not a friendly one but more of an understanding of her twisted mindset, which could add a whole new layer to the plot.