In fanfiction, Naruto has a lot of ways to escape from Akatsuki if kidnapped. He could wait for an opportunity when the Akatsuki members are preoccupied with their internal disputes. Since he has a strong bond with his friends in Konoha, they might be on their way to rescue him. Naruto could also use his unique Uzumaki bloodline abilities, like his strong life force, to endure any torture or imprisonment until he finds a way to get out. He might even discover some secrets about the Akatsuki during his captivity that could be used to his advantage.
He could use his Rasengan. If he manages to gather enough chakra secretly, he can surprise his captors with a powerful Rasengan and break free.
Naruto could use his shadow clones to create distractions. He could make a large number of clones and while the Akatsuki members are dealing with the clones, he could find an opening to escape. Also, he might be able to tap into the power of the Nine - Tails more than ever before in a desperate situation, using its strength to break free from any restraints.
Naruto could use his shadow clones to create a diversion. He might make a bunch of clones and have them attack the Akatsuki members in different directions while he tries to find a way out. For example, he could use the chaos to search for a hidden passage or a weak spot in their hideout.
Naruto could try to befriend some of the Kumo ninjas who might not be in favor of the kidnapping. By winning them over, they could help him escape. Also, he could use his knowledge of ninja techniques and his quick thinking. For example, he could use substitution jutsu to switch places with an object when the guards are not looking and then make a run for it.
Naruto could use his Rasengan to create a big enough explosion to scatter the mob and then make his escape. He might also use his speed to quickly dash through the crowd and find a hiding place.
In fanfiction, if Naruto gets kidnapped by Akatsuki, he might be used as a bargaining chip. The Akatsuki could try to exchange him for something valuable like the Nine - Tailed Fox's chakra. Or they might try to extract the Nine - Tails from him forcefully. Naruto would surely put up a fight though, using his Rasengan and other jutsu.
If Sakura gets kidnapped by the Akatsuki in fanfiction, Sasuke could also get involved. Since he has his own history with the Akatsuki, he might use his knowledge to track them down. Also, Sakura herself could be trying to find a way to escape from within. She's a strong kunoichi, after all. She might be gathering information about the Akatsuki's plans while being held captive.
Percy could look for any weaknesses in the wizards' magic or their security. Maybe there are certain times of day when their spells are less effective. He could also try to befriend a less - strict wizard who might be willing to help him escape.
Ash could use his Pokémon. Pikachu, for example, could use its electric attacks to short - circuit any devices or barriers holding Ash captive. His other Pokémon like Charizard could also help by using their strength or special abilities to break free.
Nico could initially be shocked and scared. But as he regains his composure, he would likely start to analyze the situation. He might try to communicate with the Avengers, especially if he realizes they are not pure villains. He would use his wits to find a way out of the situation while also trying to understand their motives for kidnapping him.