One plot idea could be that Amaterasu from Okami is reimagined as a powerful jutsu in the Naruto world. Naruto could accidentally discover this jutsu during one of his training sessions in a mysterious ancient ruin. Another idea is that the main characters from Okami, like Amaterasu or Issun, are transported to the Naruto universe. They could team up with Naruto and his friends to fight against a common enemy, such as Orochimaru who is seeking the power of the Okami realm. A third plot could involve Naruto visiting the Okami world and learning their unique style of combat and magic, which he then brings back to Konoha to use against the Akatsuki.
Well, a cool plot for an Okami Naruto crossover fanfiction might be that the Celestial Brush techniques from Okami are integrated into Naruto's ninjutsu. For example, Naruto could use the power of the Celestial Brush to create platforms and obstacles during a battle with Pain. Or perhaps some of the Okami characters are reincarnated as ninja in the Naruto world. They retain their memories and powers from their previous lives and join Naruto in his quest to bring peace. Also, the concept of purifying the land in Okami could be related to Naruto's goal of ending hatred in the ninja world. He could learn from the Okami way of purifying evil spirits to deal with the negative emotions in people.
One plot idea could be a crossover where Naruto gains the power of Amaterasu from Okami. He could struggle to control this new and powerful ability, facing challenges from both within his own village who fear his new power, and external enemies who want to use it for their own evil purposes.
One plot idea could be Amaterasu living among humans in her human form and using her divine powers secretly to help them. For example, she might use her ability to control nature to end a drought in a small village. Another could be her forming a friendship with a human artist who, unknowingly, starts to paint pictures that are prophetic due to her influence. A third idea is that she has to hide her identity from a group of hunters who are searching for any signs of the divine, as they believe the gods are causing chaos.
One interesting plot idea could be a crossover where Naruto's senjutsu abilities are combined with another universe's magic system. For example, if he were to cross over into the Harry Potter universe, he could use senjutsu to enhance his magic or even teach the wizards about chakra. Another idea is a crossover with the Dragon Ball universe, where Naruto's senjutsu clashes with the ki energy of the Saiyans. Maybe he has to use senjutsu to face off against a powerful Saiyan who has come to the Naruto world. Or a crossover with the Bleach universe, and Naruto uses senjutsu to interact with the spiritual energy there, perhaps even helping Ichigo in a battle against a powerful Hollow by using his unique senjutsu skills.
One plot idea could be that Naruto characters end up in Ikebukuro. For example, Naruto himself could be searching for a new type of ninja tool that he heard can only be found in Ikebukuro. Meanwhile, the gangs in Durarara start to notice this strange, orange - clad boy with strange powers. Another idea is a character swap where some of the Durarara characters gain ninja abilities and get involved in Naruto - style battles in their own world. Maybe Celty could use her shadow powers in a more ninja - like way, like stealth and quick attacks.
One idea could be that Naruto characters are transported into the Splatoon world. They might initially be confused by the ink-based battles and the unique species. For example, Naruto could mistake an Inkling for a strange ninja from another land and challenge them to a friendly spar, only to find out about the ink shooting mechanism. Another plot could involve the Akatsuki from Naruto trying to steal the valuable ink resources in the Splatoon world for their own purposes. They would face off against the Splatoon heroes who are determined to protect their world's resources.
A cool plot could be that there's a tournament across different anime worlds, and Inuyasha and Naruto are chosen to represent their respective worlds. Along the way, they discover similarities in their pasts, like both having some form of demon - related heritage (Naruto with the Nine - Tails and Inuyasha being a half - demon). They also exchange combat techniques. Naruto teaches Inuyasha how to better use chakra control in his attacks, and Inuyasha shows Naruto some unique sword - fighting skills.
One interesting plot idea could be that Kaguya is reborn in the modern Naruto world. She has no memories of her past at first. Naruto discovers her and senses a strange power within her. As she starts to regain her memories, she struggles between her old self and the new world she's in. Naruto has to decide whether to trust her or not.
Perhaps the nine - tailed fox in Naruto and the Avatar state could have some sort of connection. In the fanfiction, the two powers could interact in unexpected ways. For example, when Naruto enters his nine - tailed fox mode, Aang's Avatar state could be affected, or vice versa. They might have to learn to control these interactions to save both their worlds from a dark force that wants to use this power connection for evil.
One idea could be that Naruto gets a gamer power that allows him to level up his ninja skills like in a game. For example, he can see his progress in learning new jutsus as leveling up. Another could be a crossover with a popular game world where Naruto has to fight game bosses using his ninja abilities.
A plot could involve a villain who wants to steal the Vocaloid's voices to use as a weapon in the Naruto world. The voices could be used to control people or summon powerful creatures. Naruto and his friends would have to team up with the Vocaloid characters to stop this villain. They would need to figure out how to protect the voices and use the Vocaloid's musical powers against the villain.