A time - travel based fanfiction would also be cool. Marinette could travel back in time to Naruto's world. She might be mistaken for a strange kunoichi at first. But then she uses her creativity and Ladybug powers to help Naruto and his friends in battles, and along the way, a deep friendship or more could develop between them.
One idea could be that Naruto somehow ends up in Marinette's world. Maybe through a strange ninja jutsu gone wrong. He could then help Marinette with her Ladybug duties, using his ninja skills to fight akumas in a different way than she's used to.
Maybe Peter discovers Marinette's Ladybug identity when he's in Paris on a mission. He initially mistakes her for a threat but then realizes she's a hero too. They start training together and sharing their experiences of being young superheroes. Marinette helps Peter with his stealth skills, which are useful for his Spider - Man activities, and Peter shows Marinette some new ways to use her yoyo in combat. This could lead to a romantic relationship as they grow closer through their shared superheroics.
A more character - driven idea would be that Naruto and Yato meet and learn from each other's outlooks on life. Naruto, who has always fought for his friends and village, could teach Yato about the importance of having a strong community. Yato, who has a very different view of the afterlife and the divine, could show Naruto a whole new perspective on existence.
One interesting idea could be Orochimaru seeing Naruto as a unique specimen and instead of just trying to use him, he actually starts to respect Naruto's willpower. This could lead to a strange mentorship of sorts where Orochimaru teaches Naruto some of his more unorthodox jutsu in exchange for Naruto trying to help Orochimaru find a new path that doesn't involve so much darkness.
One idea could be a story where Naruto and Tsume go on a mission together in an unknown territory. They face various challenges and have to rely on each other's skills. Naruto's optimism might contrast with Tsume's more serious nature, creating an interesting dynamic.
Another idea is that Bayonetta somehow ends up in the Naruto universe. She might be mistaken for a powerful ninja at first. Then she could start teaching some of the ninja new combat techniques inspired by her own moves, while also learning about chakra and how it differs from her own power source.
Well, a cool concept could be that Naruto discovers Sarada has a unique power that is similar to his own but also very different. He then decides to mentor her privately, and during this process, they form a strong bond that is not just about master - student but also a deep friendship. They could also face some challenges from the village elders who are skeptical about their relationship.
One idea could be Naruto being summoned into the world of FF14. He might initially be confused but quickly adapt his ninja skills to the new environment. For example, his ability to use chakra could be translated into a unique form of magic in FF14.
In a 'naruto x renamon fanfiction', there could be a prophecy that only the combination of the power of the Nine - Tailed Fox within Naruto and Renamon's true form power can defeat an ancient evil that is about to awaken in both their worlds. They have to overcome cultural differences and language barriers at first, but as they get to know each other better, they develop a deep friendship and work towards fulfilling the prophecy.
Another idea is that Hera uses her powers to train Naruto in a different form of chakra control. This could lead to Naruto developing new and unique jutsus. For example, he might be able to combine his regular chakra with some of Hera's magic - like energy blasts with a new kind of elemental twist.
One idea could be a crossover where Naruto visits Rosario's world and they team up to fight a common enemy. Maybe a powerful demon that exists in both their universes.