One possible plotline could be a power - exchange. Naruto learns about the power of Vibranium from Black Panther and tries to incorporate it into his ninja tools. Meanwhile, Black Panther gets interested in chakra and starts training to use it.
A plotline could involve a conflict that forces Naruto and Black Panther to team up. Maybe an ancient evil that has ties to both the ninja world and Wakanda resurfaces. They have to combine their unique skills, like Naruto's Rasengan and Black Panther's claws, to defeat it. They also have to overcome cultural differences as they work together.
Another plotline could be a story of discovery. Black Panther travels to the ninja world to find a cure for a disease in Wakanda that can only be found there. He meets Naruto and they embark on a journey together. Along the way, they learn about each other's worlds, Naruto about the advanced Wakandan technology and Black Panther about the complex ninja society and its jutsu.
In a 'negima meets black panther fanfiction' plotline, the magical artifacts in Negima could be of great interest to the people of Wakanda. They might want to study them for their own technological advancements. On the other hand, the Black Panther's suit and its abilities could be something that the Negima characters are in awe of or try to replicate. There could also be a plot where a character from Negima, like Negi, tries to learn from T'Challa about leadership and in turn teaches him about magic, leading to a mutual exchange of knowledge and a unique friendship.
One possible plotline could be that Naruto is somehow transported to the Marvel universe and he meets Black Widow. They then team up to fight a common enemy, perhaps an evil ninja - like villain who has some sort of connection to Naruto's world but is also causing trouble in the Marvel world.
One possible plotline could be Tony as a panther facing off against some kind of threat to his territory. Maybe there are other supernatural creatures trying to encroach on his space.
One possible plotline could be that Henrietta, with her own set of skills and experiences, somehow gets transported to the Naruto universe. She might have to adapt to the ninja world, and Naruto could help her in this process while also learning from her in return.
One possible plotline could be that Naruto somehow gets transported to the world of satellizer. There, he might use his ninja skills to help satellizer in her battles or against her enemies.
A plotline might involve a magical or chakra - based accident that binds Naruto and Arturia together in some way. They have to figure out how to break the bond while also facing challenges that come their way. For example, they might be hunted by a group who wants to use their combined power for evil. In some fanfictions, there could also be a love triangle situation involving one of their friends or comrades from their respective worlds.
Maybe in a fanfiction, Tsunami discovers a hidden power within herself while Naruto is in the village. Naruto helps her control this power. As they train together, they start to see each other in a new light. Their relationship evolves from friendship to something more romantic as they face various challenges together.
Perhaps in a 'naruto x tifa lemon fanfiction', Tifa could be transported to the Naruto world. She might initially struggle to adapt to the ninja - based society. Naruto, being the friendly and helpful character he is, would assist her. As they spend time together, they start to understand each other's strengths and weaknesses, which could lead to a deeper connection. However, they also have to deal with the politics and power struggles in the Naruto world that might threaten their relationship.
One possible plotline could be that female Pikachu somehow ends up in the Naruto universe. Naruto, being the curious and friendly guy he is, befriends her. They then team up to face a common enemy that is causing trouble in both the ninja world and Pikachu's world. Another could be a more light - hearted plot where Pikachu's electric powers are used in the Naruto world in a comical way, like helping Naruto prank his friends or power up some of his jutsu in unexpected ways.
One possible plotline could be Naruto being sent to the Hazbin Hotel universe by some sort of magic or accident. He might then try to use his ninja skills to survive in this new and strange world filled with demons and sinners.