Maybe a story where Naruto discovers an ancient battleship that has some sort of chakra - powered technology. He then has to figure out how to use it to defend the Hidden Leaf Village from an approaching fleet of enemy ships led by a new and unknown threat.
Another interesting concept is a crossover within the Naruto universe. For example, Naruto and his friends find themselves on a battleship in a world that has elements of the Land of Waves and some advanced technology. They must adapt to this new environment and use their skills to survive.
Another plot could involve a race between different teams in RWBY to claim a powerful battleship. This battleship could hold the key to some great power or knowledge. Along the way, they face various challenges and obstacles, both from each other and from external forces.
One idea could be a crossover with Star Trek. The Yamato crew could encounter the USS Enterprise and have to work together to face a common enemy, like a powerful alien race that is threatening both their galaxies. They might have to learn from each other's technology and ways of handling situations.
Perhaps a fan fiction where the Yamato is suddenly invaded by a group of shape - shifting aliens. These aliens can take on the form of the crew members, causing chaos and paranoia on the ship as no one knows who is real and who is an impostor. The remaining real crew has to find a way to identify and defeat these aliens.
Yes, there are likely fanfictions out there where Naruto has a battleship. Fanfiction writers often come up with creative and unique scenarios, and this could be one of them. They might use this idea to create new adventures for Naruto, perhaps having him use the battleship in a fight against powerful enemies or on a special mission. However, it might not be a very common concept, but with the vastness of the fanfiction world, it's definitely possible.
One interesting plotline could be a massive wizarding battleship battle where Hogwarts students and Death Eaters engage in a sea - based fight. The battleship could be enchanted with all sorts of magic, like shields made of Patronus charms.
One interesting idea could be the combination of Naruto's ninja skills with mecha technology. For example, Naruto might use his chakra to power up the mecha in unique ways. Another idea could be the new enemies that are created specifically for this mecha - Naruto concept, like robotic shinobi that require different combat strategies compared to normal foes. Also, the design of the mecha Naruto itself can be really cool, perhaps with features inspired by the Nine - Tails.
Another idea is that Aizen somehow ends up in the Naruto universe during the time of the Fourth Great Ninja War. He could try to manipulate both sides for his own gain. But Naruto, with his ability to see the good in people, might try to reason with Aizen and show him a different path. It could be a story of redemption or a great battle if Aizen refuses.
In a 'Naruto Mermaid Fanfiction', the mermaids could be in danger from an evil organization that wants to capture them for their precious scales. Naruto teams up with a mermaid princess to stop this threat and in the process, they learn about each other's worlds.
One idea could be a crossover where Naruto and Pucca end up in the same world due to a strange ninja jutsu gone wrong. Naruto is confused by Pucca's constant chasing of Garu, and he tries to help Garu escape in his own Naruto - style way.
Well, you could write a fanfiction where the Nine - Tails in Naruto has some sort of connection to a powerful entity in the Seraphim universe. This connection could lead to a series of events that require Naruto and the Seraphim characters to work together. Or perhaps a character from Seraphim is reincarnated as a ninja in the Naruto world and has to adapt to the new way of life while still having some of their Seraphim abilities.