The Hidden Leaf Village as a whole might mobilize to rescue Naruto. He is an important asset to the village, being the host of the Nine - Tails. So, the Hokage at that time could send out a team of elite ninjas, including some of the Jonin and Chunin, to get Naruto back safely from the Akatsuki's clutches.
Sasuke could be a likely candidate. Despite their differences, Sasuke and Naruto have a deep connection. He might hear about Naruto's capture and come to his rescue, driven by their past friendship and the rivalry that also binds them.
It could be other villages as well. Since Naruto has made friends and allies from different villages during his adventures. For example, the Sand Village might send some of their ninja to help, considering Naruto's relationship with Gaara.
It's possible that some unexpected characters could come to Naruto's rescue. For example, an old enemy of the Akatsuki who has a change of heart. Or perhaps some of the Jinchuriki who Naruto has befriended in the past. They might feel indebted to Naruto for his kindness and decide to help him out of the Akatsuki's clutches. There could also be a mysterious and powerful hermit ninja who hears about Naruto's capture and decides to intervene for the greater good of the ninja world.
In this type of fanfic, Hinata could also play an important role. Her love for Naruto might drive her to take risks to save him. Additionally, the members of the Akatsuki like Deidara and Hidan would be key characters as they are directly involved in Naruto's capture and the events that follow. They could provide a lot of conflict and action in the story with their different personalities and abilities.
Maybe a rogue ninja group that wants to sell Naruto to the highest bidder. They see him as a valuable asset due to his strength and status in Konoha.
His friends from Konoha like Shikamaru and Choji could help. Shikamaru is smart and can come up with great strategies, while Choji can provide brute strength in battles.
The rest of Team 7, like Sakura. She may not be as strong as Sasuke or Naruto, but she has a strong will. She'd be worried sick about Naruto and would do whatever she could to help in the rescue. Plus, she might be able to use her medical skills to treat Naruto if he's injured during the kidnapping situation.
Maybe some of the more conservative village elders. They have always been a bit wary of Naruto because of the Nine - Tails inside him. So they might be behind his capture in the fanfiction.
Well, it could go in many directions. For one, the Akatsuki might hold Naruto captive to use him as a bargaining chip against Konoha. They could demand things like the village's secrets or other powerful ninja in exchange for Naruto's life. Or perhaps some members of the Akatsuki would have a change of heart and decide to protect Naruto instead of following their original plan.
Well, in the fanfiction, if Naruto is captured by the Akatsuki, they might try to extract the Nine - Tails from him. They could use various cruel methods. But Naruto being Naruto, he would never give in easily. He would keep fighting back with his willpower, trying to find a way to escape or at least cause some trouble for the Akatsuki members while in captivity.
Well, Naruto might be interrogated for information about the Hidden Leaf. The Akatsuki are always after secrets, especially about the Jinchuriki. So they could be trying to find out more about the Nine - Tails within Naruto.