A common plot point is the culture shock. For example, Naruto characters being shocked by the dark and often cruel nature of the Overlord world. Another is the power - up concept. Naruto might gain new powers related to the Overlord's magic system. It makes for some really cool fight scenes.
One really engaging plot point is the interaction between the two different forms of combat. Ninja techniques and Overlord magic are very different. When these are pitted against each other or combined, it creates some truly unique and exciting scenarios. For instance, Naruto using his shadow clone jutsu in combination with an Overlord - style spell. This kind of cross - over in combat mechanics is a big draw in these fanfics.
Well, in some 'naruto x vocaloid fanfic', a common plot point is the sharing of abilities. For instance, Naruto might gain the ability to create Vocaloid - like melodies that can soothe or inspire his comrades, just like how Vocaloid characters can influence emotions with their songs.
A third idea is a fusion of the two worlds. The shinobi villages and Nazarick could form a trade or knowledge - exchange system. Characters from both sides would have to learn about each other's cultures and abilities. This could lead to some really fun interactions, like Albedo trying to learn ninjutsu from Kakashi, or Sasuke being intrigued by the power of the Supreme Beings in the Overlord world.
Another plot point could be a love triangle. Suppose there's another character who has feelings for Naruto and is jealous of his growing relationship with fem Itachi. This could create a lot of drama and tension in the story. Also, the backstory of the fem Itachi could be different from the male Itachi's. Her reasons for being involved in certain events in the Naruto world could be a major plot point, like if she has a personal vendetta against a particular group or person.
One interesting plot point could be the combination of Naruto's chakra system with the magic in Re:Zero. For example, how would Naruto's jutsu work in a world where magic like Crusch's exists? Another is the cultural clash. Naruto comes from a ninja village with its own values and Re:Zero has its own set of social norms. How do the characters navigate this difference?
Well, one possible interesting plot point could be the unique bond that forms between Naruto and Kyuubi in a non - traditional way. Maybe they have to work together to overcome a new and powerful enemy that neither could face alone.
One interesting plot point is how Naruto's ninja training regime might influence the school's physical education class in the 'School Days' setting. Another is how his loyalty to his friends in Naruto is translated into relationships in the school environment of 'School Days'.
Another plot point might be Lucoa sharing her dragon - related knowledge with the ninja. This could lead to new jutsu being created or new ways of thinking about power in the Naruto universe. For example, she might teach about dragon - like breathing techniques that could be incorporated into ninja training.
A really interesting plot point in 'Naruto' drunk fanfic is the exploration of the character's emotions. When drunk, Naruto might show his insecurities more openly. He could start talking about his feelings towards Sasuke in a more raw and unfiltered way. This can create some really emotional and deep moments in the fanfic, as his friends listen and support him, or sometimes are shocked by what he reveals.
Often, the exploration of Konan's unique paper - based jutsu is an interesting plot point. In many fanfics, she uses it in creative ways in battles alongside Naruto. For example, in some, she creates paper constructs to help Naruto with his training. Another is the development of their relationship. It could start as mutual respect and grow into a deep friendship or something more, like in 'Naruto and Konan: Unlikely Love' where they fall in love over the course of their adventures.
A possible interesting plot point is Naruto having to adapt his chakra control in the Martian atmosphere. Since Mars has different conditions than Earth, his jutsu might work differently. Another could be Naruto encountering Martian life forms and having to communicate or fight them using his ninja skills.