Maybe Naruto in the Anbu stumbles upon a monster that has the ability to possess people. This leads to a mystery as he tries to find the source of the monster and free those who are possessed. He might face opposition from within the village who don't want the truth to come out.
One idea could be that Naruto, as a young Anbu, discovers a hidden monster within the village that is being used for secret experiments. He then has to figure out how to stop the monster from causing chaos without revealing the village's dark secret.
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.
One idea could be Naruto going on an Anbu mission where Hinata secretly follows him to protect him. Another could be an alternate universe where Naruto and Hinata are both in the Anbu and they have to work together to solve a mystery within the Hidden Leaf. Or perhaps a story where Naruto is in the Anbu and Hinata is trying to get his attention in a more covert way than usual.
One idea could be that the blind Anbu has a special ability to sense chakra in a unique way. For example, they can detect the slightest change in an enemy's chakra, even if they can't see them physically. This gives them an edge in battle.
A really interesting plot could be that the ANBU commander discovers a long - forgotten prophecy that somehow involves the ANBU and the future of the Hidden Leaf Village. They then embark on a journey to understand the prophecy better, facing many obstacles along the way, including opposition from some within the village who fear the changes the prophecy might bring.
One plot idea could be a Kitsune Anbu agent who has a special mission to protect Naruto but has to hide their true Kitsune nature from him at first. Another could be a Kitsune Anbu being sent to infiltrate an enemy organization that is targeting Naruto and his friends. Or perhaps a story where a Kitsune Anbu discovers a long - lost secret about Naruto's family that has been hidden by the Anbu for years.
One idea could be exploring Itachi's time in ANBU and how Naruto might have influenced his decisions secretly. Maybe Naruto, with his unique way of seeing people, could have made Itachi question his path in the ANBU more deeply.
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.
One idea could be exploring the character's past in the ANBU in more detail. For example, showing the difficult missions they had to undertake and how it shaped them.
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.
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.