Well, the plot could start with Goku sensing a strange energy in a different dimension, which turns out to be Naruto's. Goku goes to investigate and finds Naruto struggling with his own inner demons, like the Nine - Tails. Goku, having experience with his own inner beast - like power (the Great Ape), helps Naruto come to terms with it. Goku then takes Naruto back to his own world to train him. Naruto gets to experience the Dragon Ball world, meets Goku's friends and family. He learns about Goku's training regime and starts to incorporate it into his own. Eventually, they return to the Naruto world and Naruto is a much stronger and more confident ninja, ready to protect his village in new ways.
In a 'Goku adopts Naruto' fanfiction, perhaps Goku accidentally travels to the Naruto universe. He comes across Naruto, who is an outcast in his village at that time. Goku, not understanding the social structure but seeing Naruto's potential and loneliness, decides to adopt him. Goku teaches Naruto about the concept of Super Saiyan and how to harness his inner power in a different way. Naruto, in turn, shows Goku the beauty of ninja techniques. They might end up fighting against the Akatsuki together, with Naruto using his newfound Saiyan - like strength and Goku using some ninja - inspired moves.
One possible main antagonist could be Frieza. Imagine if Frieza somehow found his way into the Naruto universe. He would be attracted to the chaos and power struggles there. Goku and Naruto would have to team up to stop him from taking over the Naruto world. Frieza's cold - blooded nature and his desire for power would put him at odds with our heroes. His powerful abilities would be a huge threat to both Naruto and Goku, especially since Naruto is still learning about the new powers Goku is teaching him.
In some fanfictions where Sakura adopts Naruto, it could be about Sakura seeing Naruto's need for a family. Maybe she decides to take him in after realizing how alone he has been. This can lead to a lot of character development for both of them. Naruto might start to heal from his past traumas, and Sakura could grow into a more nurturing figure.
The plot could also revolve around the Akatsuki protecting Naruto from other threats in the Naruto world. Perhaps there are other forces that see Naruto as a threat, and the Akatsuki, despite their own reputation, step in to keep him safe. This could lead to some interesting battles and alliances, as the Akatsuki has to face off against their former allies or new enemies all while taking care of Naruto.
One possible plot could be that Naruto discovers an orphaned child during one of his missions. The child has unique chakra abilities but is shunned by the village. Naruto, remembering his own childhood of being an outcast, decides to adopt the boy. He then trains the boy not only in ninja skills but also in values like friendship and perseverance.
Well, one possible plot could be that Naruto discovers an orphaned baby during one of his missions. He decides to take the baby in because he understands what it's like to grow up without parents. He then has to learn how to take care of a baby while still being a ninja. Maybe he gets help from his friends like Sakura who gives him medical advice for the baby's health, and Kakashi who gives him some wisdom on raising a child.
In a 'Naruto adopts Koneko' fanfiction, the plot could involve Naruto finding Koneko in a difficult situation. Maybe she's lost in the ninja world. Naruto, with his big heart, decides to take her in. He'd teach her ninja skills and his own values of hard work and friendship. Koneko might struggle to adapt at first, but with Naruto's support, she'd start to grow. And they could go on adventures together, facing various enemies and challenges in the process.
Well, if Naruto adopts Sarada in a fanfiction, it could start with Sarada facing some difficulties in her relationship with her mother, Sakura. Naruto, having grown up without parents himself, empathizes with her. He adopts her and takes her on adventures outside the village. This would expose Sarada to different cultures and ninja techniques. Along the way, they would form a deep bond, and Sarada would become more like Naruto in her positive attitude towards life and determination to protect the village.
Well, one possibility could be that Kakashi takes Naruto under his wing and starts training him more intensively. He might teach Naruto some of his own special jutsu and also help him deal with his inner demons related to being an orphan. Another aspect could be Kakashi helping Naruto with his schoolwork at the ninja academy, which in turn helps Naruto gain more respect from his peers.
Maybe Hiashi adopts Naruto because he realizes that Naruto is a key to uniting the village. As Naruto becomes part of the Hyuga family, he starts to influence the clan's view on outsiders. He might introduce some new training methods that he learned from Jiraiya. Naruto could also have a role in protecting the Hyuga's secrets, like the Byakugan. He would grow in a different environment, and this would change his relationships with characters like Sasuke and Sakura in new and unexpected ways.
One possible plot could be that Nagato, seeing Naruto's potential and his kind heart, decides to take him under his wing. He could teach Naruto different jutsus and his unique view of the ninja world. This would change Naruto's growth path as he'd be influenced by Nagato's experiences and beliefs.