A cool plot could be that Team 7 in ANBU gets a mission to rescue a group of kidnapped ninjas from a powerful and elusive enemy. Naruto has to master a new form of his Rasengan to fight this enemy. Sakura trains hard to be able to hold her own in combat against highly skilled opponents. Sasuke unlocks a new power in his Sharingan during the mission. And throughout the mission, they learn more about the history of the ANBU and the secrets that Konoha has been hiding.
Maybe in the fanfiction, the ANBU Team 7 is sent on a mission to infiltrate a hidden organization that is planning to attack Konoha. Naruto uses his shadow clones in creative ways to gather intelligence. Sakura disguises herself as a member of the organization and uses her knowledge of poisons to take out guards silently. Sasuke uses his Sharingan to detect hidden traps and enemies. Along the way, they discover that there is a traitor within Konoha who is feeding information to the enemy.
Another plot could involve the Anbu team being tasked with protecting a young and powerful ninja from another village who has valuable knowledge. Along the way, they form an unexpected bond with this ninja and learn new techniques from them.
Maybe in the fanfic, Team 7 in ANBU is tasked with protecting a powerful and important shinobi from another village who has come to Konoha for peace negotiations. Naruto tries to befriend the visiting shinobi, Sasuke is constantly on guard against any possible threats, and Sakura is ready to heal any injuries in case of an attack. There could be internal conflicts within Team 7 as they deal with different approaches to protection.
You might consider adding Tenten to the team. She has a vast knowledge of weapons which could be handy in various missions. And Kiba, with Akamaru by his side, could offer enhanced senses and tracking abilities for the Anbu team.
It could be Orochimaru. He has always been interested in Sasuke and might target ANBU Team 7 to get to him. Orochimaru's experiments and his desire for power make him a formidable and menacing villain. He could also be using some new jutsu or have created more powerful minions to fight against Team 7.
Well, one major plot change could be in the power dynamics. Since Naruto in Anbu is likely more skilled and experienced. He might take a more dominant role in Team 7's missions. For example, he could quickly assess and handle dangerous situations that the original Team 7 might struggle with. This could also change the relationships within the team. Sasuke might be more competitive towards Naruto, seeing him as an even greater rival. And Sakura might have more admiration or fear towards Naruto because of his Anbu status.
One possible plot could be Naruto retiring from the ANBU due to the toll it has taken on his mental and physical health. He might then focus on mentoring the next generation of ninja in Konoha, sharing his unique skills and experiences.
One possibility is that Naruto joins the Anbu to prove himself even more. He might face challenges like learning the stealthy ways of the Anbu which are very different from his usual open - combat style. He could also be sent on dangerous solo missions that test his limits both physically and mentally.
One possible plot twist could be that Naruto has to keep his ANBU identity a secret from his teammates, even during dangerous missions. This would add a layer of tension and internal conflict for Naruto as he struggles between following ANBU protocol and being a true teammate. Another twist could be that the Hidden ANBU has an ulterior motive for placing Naruto in Team 7, perhaps to spy on Kakashi or one of the other members. This would lead to a complex web of mistrust and mystery within the team. Also, Naruto might have special ANBU - related abilities that are awakened during crucial moments in the story, abilities that not only surprise his enemies but also his own team, changing the dynamics of how they approach battles and missions.
Sasuke might be a bit jealous at first. He's always been competitive with Naruto, and seeing Naruto in a special and elite unit like ANBU could trigger that jealousy. He might try to prove that he's just as good or better. Sakura, on the other hand, would probably be worried. She cares a lot about Naruto and ANBU missions are often dangerous.
In the ANBU after leaving Team 7, Naruto will be confronted with numerous challenges. Physically, the missions are likely to be more intense, requiring him to further develop his skills and combat abilities. He'll need to learn new stealth techniques and master different types of weapons. Emotionally, he'll face isolation. ANBU work is solitary, and Naruto, who thrived on the camaraderie of Team 7, will have to adjust to being alone most of the time. Additionally, he'll be faced with complex political situations within the ANBU organization. He'll have to navigate through power struggles and different factions, all while trying to stay true to himself and his values.