One idea could be Sasuke leading an Anbu mission while Naruto, as Hokage, has to deal with the political fallout of the mission's actions. For example, if the Anbu under Sasuke's command accidentally cross a border during a pursuit, Naruto has to smooth things over with the neighboring village.
Perhaps there's a fanfiction where Sasuke, as part of the Anbu, uncovers a conspiracy within the village. He reports to Naruto, the Hokage. Together, they start to dig deeper, only to find out that some of the most respected elders in the village are involved in a plot to undermine Naruto's leadership for their own gain.
Perhaps in the fanfiction, there's a prophecy that only Hokage Naruto and Anbu Sasuke can fulfill together. They have to embark on a dangerous journey outside the village to prevent a great disaster. Along the way, they face many challenges that test their friendship and skills. For instance, they might have to fight against ancient and powerful creatures. This would not only show their combat abilities but also how they support each other in difficult situations.
One idea could be that the daughter of an Anbu member is discovered to have a unique Kekkei Genkai. This leads to her being closely watched by the Hokage, Naruto in this case. Maybe she has the power to manipulate time on a small scale, which could create all sorts of interesting scenarios in the ninja world. For example, she could use it to prevent small disasters or help in battles without others realizing how she's doing it at first.
One idea could be Naruto and Sasuke teaming up to face a new, powerful and ancient threat that even the combined might of the Hidden Villages can't handle easily. They have to use their unique skills and the bond they've reforged as Hokage and his equal.
A great plot could be that there is a curse that starts to affect all the ninja in the village and only Naruto and Sasuke's combined chakra can break it. They must embark on a journey to find the source of the curse. Along the way, they discover secrets about the past Hokages and how to better lead the village. Or perhaps a plot where Sasuke, who has been away from the village for a long time, returns and is shocked to see Naruto's new Hokage - like leadership style. He decides to challenge Naruto not in a fight but in a contest of who can better protect and improve the village, leading to a series of events that show their different approaches.
One idea could be that Naruto and Sasuke are assigned a top - secret ANBU mission together to infiltrate a hidden enemy base. They have to rely on their unique skills and their new - found understanding of each other as ANBU operatives. Another could be that they are both part of an elite ANBU squad and have to deal with a powerful rogue ninja who has ties to their past.
Another plot could be set after Naruto becomes Hokage. Itachi somehow returns or his past actions are re - examined in a new light. Naruto, as the Hokage, has to deal with the revelations about Itachi and how they impact the village's history and relationships. They might work together to heal old wounds and face new challenges that are related to the past secrets of the Uchiha clan.
One idea for the main plot is that a group of rogue ninjas has developed a new and dangerous jutsu that can disrupt the balance of power in the ninja world. Naruto, in his role as Hokage, decides to take action. Sasuke, as an Anbu, is sent to infiltrate the group. As Sasuke gets closer to the truth, he finds that the leader of the rogue ninjas has a personal vendetta against Naruto. This forces Sasuke to race against time to stop the jutsu and protect Naruto and the village. Along the way, Sasuke also has to come to terms with his own past actions and how they might affect the current situation.
A really interesting fanfiction idea could be that Sasuke in the Anbu discovers a conspiracy within the village that even Naruto as Hokage is unaware of. Sasuke then has to decide whether to go to Naruto directly or investigate further on his own. This would create a lot of tension and drama, as Sasuke's loyalty to the village and his relationship with Naruto are both at stake.
One possible scenario in such a fanfiction could be Naruto as Hokage having to deal with political situations in the village while Sasuke, as an Anbu, is sent on dangerous covert missions. Naruto might rely on Sasuke's intelligence and combat skills from his Anbu work to protect the village from external threats. They could also have some internal conflicts due to their different roles and the secrecy associated with Sasuke's Anbu work.
One idea could be that Anbu Naruto is assigned to protect Female Sasuke during a dangerous mission. As they work together, they start to understand each other's past traumas and form a deep bond. Another plot could be a scenario where they are both on opposing sides initially in a political conflict within the village, but gradually realize they have more in common than they thought and end up teaming up to bring about change. And perhaps a plot where they are training together secretly and discover new jutsus together, which in turn deepens their relationship.