A great appropriate theme would be the relationships between the characters in a non - romantic or non - vulgar way. Such as how Naruto, Sasuke, and Sakura strengthen their friendship through various trials and challenges they face together. This focuses on the core values of the show like camaraderie and loyalty.
One positive theme could be about Naruto's training in new and unique ninja techniques. For example, a fanfic could explore how he masters a powerful and ancient jutsu that was lost for centuries. This would stay true to the action - adventure and growth aspects of the series.
A great topic would be exploring the backstories of some of the minor characters in more depth. Like how a certain side character became a ninja, what their family was like, and what motivated them to be part of the ninja village. This can add more richness to the Naruto universe. Another idea is to write a fanfic about Naruto and Sasuke's friendship after the end of the main series, showing how they continue to support each other and grow as comrades in a more peaceful era.
A great appropriate theme is the exploration of different cultures within the Avengers. For instance, Thor's Asgardian culture or Black Panther's Wakandan culture. Fanfics can use these cultural elements to create rich storylines. Also, fanfics can focus on the Avengers' mentorship relationships, like how an older Avenger might mentor a younger one. This can be really inspiring. And the theme of hope is always good in fanfics. It can show how the Avengers give hope to the world in the face of great danger.
A theme about Naruto's impact on the Hidden Leaf Village is also great. It could cover how his positive attitude and determination inspire the villagers, and how he changes the village for the better over time.
Friendship is also a great theme. Fanfics can center around the strong bonds between Naruto and his friends like Sasuke and Sakura. They could show how their friendships endure through difficult times and how they support each other in their respective quests.
Well, a great positive theme is redemption. There are characters in Naruto who have made mistakes and then seek to make amends. Fanfic can expand on these redemption arcs, showing the journey of a character from a wrongdoer to someone who is trying to do good. Also, the theme of family, whether it's the found family aspect like Team 7 or the idea of Naruto's search for his own family roots, can be beautifully explored in fanfic.
Positive fanfic themes might include the backstories of minor characters. For instance, delving into the past of Rock Lee and how his determination to become a great ninja despite not having natural ninja abilities. Or it could be about the rebuilding of the Hidden Leaf Village after the various battles and how different characters contribute to this process.
Teamwork is also a great theme. A fanfic might depict how Team 7 (Naruto, Sasuke, and Sakura) work together to overcome a powerful enemy that they couldn't defeat alone. Additionally, exploring the backstories of minor characters in a positive light can be interesting, such as a fanfic about how Iruka Sensei became a teacher and his influence on Naruto's early days.
Another theme could be a time - travel fanfic where Naruto and Sakura go back in time. They use their knowledge of the future to change some events for the better. This allows for a lot of character development as they see their past selves and try to guide them. It also gives an opportunity to explore their relationship in a new and interesting way.
A theme about their friendship and how it endures over time. They could face various challenges in the Hidden Leaf Village, and their bond could be the key to overcoming those difficulties. For example, they might have to work together to protect a precious artifact of the village.
One popular theme is exploring the backstories of characters in more depth. For example, delving into how Kakashi became the skilled ninja he is. Another is alternate universe stories where the characters have different roles or relationships. And also, fanfics about team - building and the growth of the bonds between Naruto and his friends like Sasuke and Sakura.