Well, perhaps Harry Potter, with his knowledge of magic and a big heart, finds Naruto in the wizarding world. Maybe Naruto's chakra could be seen as a unique form of magic there. Harry could take Naruto under his wing, teach him about the wizarding ways, and Naruto could in turn show Harry some of his ninja skills. They could team up to fight dark wizards and evil ninja forces that somehow cross over into each other's worlds.
Definitely Hermione. She's so smart and curious that she'd be all over Naruto's abilities. She might even try to write a book about it. And then there's Sirius Black. He could be like a cool uncle figure to Naruto. In Naruto's world, Jiraiya would be a must - include. He could have a great time exploring the wizarding world and flirting with witches. He might also teach Harry some of his unique ninja skills.
A 'Harry Potter adopts Naruto' fanfiction could see Naruto being amazed by the magic of the wizarding world. He might constantly ask Harry about how everything works. Harry would have to explain things like the Floo Network and thestrals to him. Naruto could also share his stories of the Hidden Leaf Village with Harry and his friends. This could lead to new friendships being formed, like Naruto becoming good friends with Ron and Hermione. And perhaps Naruto would use his shadow clone jutsu to help out during Quidditch matches, either by confusing the opposing team or helping to search for the Snitch.
One possible plotline could be that the female Harry Potter stumbles upon Naruto's world through some sort of magical accident. She then realizes Naruto's situation and decides to take him under her wing, teaching him about magic in the process. Another could be that she is sent on a mission to Naruto's world for some magical reason and sees Naruto's potential and adopts him as her protege to help him grow stronger both in ninja skills and, with her help, in magic as well.
The story could start with Harry finding Naruto in some sort of strange situation, like he accidentally gets transported to the wizarding world. Then Harry decides to take Naruto under his wing. As they spend time together, Naruto would start to learn about magic, and Harry would learn about Naruto's ninja skills. Their friendship would grow, and they would face various challenges together. Maybe they would have to deal with a dark wizard who is interested in Naruto's unique abilities. And along the way, Naruto would make friends with other Hogwarts students, like Neville, and they would all learn from each other.
Well, it could be really interesting. Maybe Fem Harry Potter, with her magic skills from the wizarding world, would introduce Naruto to a whole new realm of possibilities. She could use magic to help Naruto in his ninja training, like creating magical obstacles for him to overcome. And perhaps she'd also share her knowledge of fighting dark forces with Naruto, and together they'd face new threats that combine the evils of the Naruto world and any potential dark wizards that might cross over.
One exciting element is the clash of two different power systems. Magic from Harry Potter's world and chakra from Naruto's world. Seeing how they interact when Fem Harry Potter tries to train Naruto or when they face an enemy together is really thrilling. Another is the cultural exchange. Naruto's ninja way and the values of the wizarding world are so different. Watching Naruto introduce things like ramen to Hogwarts students and seeing wizards show Naruto magical creatures would be super fun.
Perhaps Bruce Banner adopts Harry Potter after the events at Hogwarts. He takes Harry to the world of science, showing him things like advanced laboratories and scientific research. Harry, in turn, shows Bruce the wonders of magic. Their bond grows as they learn from each other, and together they face new threats that combine elements of both the magical and scientific worlds.
It could be a young wizard who lost their parents during the final battle against Voldemort. Harry feels responsible for all the orphans created by the war and decides to take this particular child under his wing.
One great fem Harry Potter crossover Naruto fanfiction is 'The Potter-Namikaze'. It combines the magic of the Harry Potter world with the ninja skills of Naruto. The story follows a female Harry Potter who somehow ends up in the Naruto universe and has to adapt. It's full of interesting character interactions and unique plot twists.