One common theme is the exploration of their self - discovery. Since they are the same person in a sense, they can see different aspects of themselves. For example, one Naruto might be more confident while the other is more reserved, and they learn from each other.
The plot could revolve around a tournament where powerful beings from different universes are invited to compete. Naruto, Ben 10, and Gwen all participate. Naruto showcases his ninja techniques, Ben shows off his alien transformations, and Gwen displays her magic. As the tournament progresses, they start to form alliances outside of the competition. They discover a conspiracy behind the tournament, where the organizers are planning to use the power of the participants for their own evil purposes. So, they decide to work together to stop this threat.
Well, one interesting aspect could be the different power sets. Naruto's ninja abilities combined with the wacky technology of Futurama. And if we consider the addition of Leia, her leadership skills could add a new dynamic to the story.
One possible plotline could be that Addy somehow gets transported to the Naruto world. Maybe she has to learn about chakra and ninjutsu while also using her skills from Z Nation to survive in this new and strange place.
A more complex plot might be that Naruto's presence in the Fallout 4 world starts to change the balance of power. His positive energy and strong will begin to inspire the people in Piper's settlement. Meanwhile, Piper helps Naruto understand the political and social dynamics of the wasteland, and together they try to bring peace and unity among the different factions.
There's also 'Fem Naruto's Adventure'. This fanfic often delves into how fem Naruto's character traits, which are a blend of Naruto's original ones but with a feminine touch, interact with Naruto himself. It could show unique storylines like how they face challenges together in a new light.
Another element is the reaction of other characters to this unique pairing. How do Sasuke, Sakura, and others in the Naruto world view the relationship between Naruto and Fem - Naruto? It often adds an interesting layer of complexity to the story, as their reactions can range from confusion to acceptance.
The theme of sacrifice also shows up a lot. Both Naruto and Sasuke are characters who are willing to sacrifice for the other in the original story, and this is often explored further in fanfiction. Writers might create scenarios where one has to make a big sacrifice for the other, which then tests and deepens their relationship.
Well, in these fanfictions, a frequent theme is the power of connection. The connection between the two Narutos is often depicted as something that gives them strength. Another common theme is the struggle against society's norms. Since it's a yaoi relationship, they may face opposition from the ninja world, which leads to themes of fighting for their relationship. Also, the theme of growth is present. They grow both as individuals and as a couple throughout the story.
There's a fanfic titled 'Naruto and Kushina: Bond Beyond Time'. In this, the author plays with the idea of time travel. Naruto gets to interact with Kushina in the past, and it's full of emotional moments as they get to know each other in a different context.