One possible plot could be that Naruto and his team are sent to the Hellsing universe on a mission. They encounter Alucard and his group. Naruto, with his ninja skills and strong will, might initially be seen as a threat by the Hellsing crew. But as they learn about his world and his fight for peace, they start to work together. Maybe Naruto tries to understand Alucard's vampiric nature and in turn, Alucard is intrigued by Naruto's chakra and jutsu. Together, they could face a new threat that is endangering both their universes.
Well, a plot could involve a dark force in the Naruto universe that has some connection to the undead in the Hellsing world. The Hellsing Organization discovers this link and sends Alucard to investigate. In the Naruto world, he meets Naruto. Naruto, being the hero he is, decides to help Alucard figure out what's going on. They find out that an ancient evil is trying to merge the two worlds and create chaos. Naruto uses his Rasengan and other jutsus, while Alucard uses his vampiric powers to fight off the minions of this evil. And they have to find a way to stop the merger of the two worlds.
One possible plot is that there is a breach between the Naruto universe and the Hellsing universe. This causes chaos as demons from Hellsing start to invade Konoha. Naruto, being the hero, tries to figure out how to stop them. Alucard arrives, not entirely as an ally at first. But as they both realize the common threat, they join forces. Naruto learns about the different nature of the enemies from Alucard and adapts his ninja skills accordingly.
The plot could be that Naruto is somehow transported to the Hellsing universe. He starts off as an outsider but quickly proves his worth. His rasengan could be adapted to be effective against vampires, perhaps by infusing it with holy water or some other vampire - weakening element. Naruto's presence could also introduce a new dynamic to the relationships within the Hellsing organization, and he might even form an unexpected bond with Seras Victoria as they both have a strong sense of loyalty and a desire to protect the innocent.
One idea could be a battle between the forces of Hellsing and some unique threat from the Alexandee universe. Maybe the Hellsing crew has to deal with a powerful magic user from Alexandee who is causing chaos in their world.
Well, perhaps in this fanfiction, the SAO system is corrupted by an Orochimaru - like figure. He wants to use the virtual world to gain power and immortality. Naruto and his friends, along with the SAO players, have to team up. Naruto's positive attitude and never - give - up spirit inspire the SAO players. They all work together to defeat this new threat, with Naruto using his Rasengan in new and creative ways within the SAO world.
A plot could involve the Killzone characters getting access to chakra. Some of the Killzone soldiers might start to learn ninjutsu and this causes chaos in their own military structure. Meanwhile, Naruto has to figure out how to get back to his own world while also dealing with the new threats that this crossover has created. Maybe he teams up with some of the more honorable Killzone soldiers to find a solution.
A plot might involve Naruto being sent to Bayonetta's world. He'd be out of his element, but his determination would shine through. Bayonetta could mistake him for a strange demon at first. However, they soon realize they can help each other. Naruto's chakra could interact in unexpected ways with Bayonetta's magic. Together, they could face off against Bayonetta's foes, like the angels, with Naruto's Rasengan combined with Bayonetta's Witch Time abilities making for some epic battles.
In a Naruto and Spiderman crossover, it could start with Spiderman noticing some strange energy signatures in his city. These turn out to be Naruto's chakra flares. Naruto is there looking for a way back to his own world after being accidentally sent to Earth - 616 (the Marvel Universe). They meet and at first don't understand each other. However, when they see a common enemy, a group of ninjas - like mutants who are causing chaos, they decide to work together. Spiderman uses his agility and web - shooting while Naruto uses his jutsu to defeat the bad guys.
One possible plot could be that Naruto and his team are on a mission in a strange new land that turns out to be the world of Claymore. They encounter Claymores, the half - human, half - yoma warriors. Naruto, with his never - give - up attitude, tries to understand the complex relationship between humans and yoma in this world. He could end up befriending some of the Claymores and together they fight against a powerful common enemy that threatens both their worlds.
One possible plot could be that Naruto, while on a mission, somehow gets transported to the world of Undertale. He teams up with Frisk to stop Flowey from taking over both their worlds. Naruto's ninja skills, like his shadow clones, could be used in creative ways in the battles against the monsters in Undertale.
One possible plot could be that Guts from Berserk is somehow transported to the Naruto universe. He might initially be seen as a threat due to his menacing appearance and his large sword. However, as the story progresses, he could team up with Naruto and his friends to fight against a common enemy, like an Akatsuki member who has acquired some of the dark magic from the Berserk world. Guts' fighting skills and his ability to face the most terrifying foes could inspire Naruto and give him new perspectives on combat.