Temari could be the most interesting. She's strong - willed and confident. In a high school fanfiction, she could be the one who challenges the status quo, like standing up against unfair school rules. Her relationship with Naruto would be a contrast, as she tries to keep him in line while also being drawn to his free - spirited nature. And she could have her own insecurities that are revealed as the story progresses, like her fear of not living up to her family's expectations in this new high school environment.
Naruto himself would be very interesting. His energetic and determined personality would contrast greatly with the more laid - back and technology - dependent Jetsons. He could bring a sense of adventure and action to their world, and his ninja skills would be something completely new for them to experience.
Chitoge could also be a great focus. Her tough - exterior - but - soft - inside personality would be really fun to explore in the Naruto universe. Maybe she could learn some of Naruto's values like never giving up and it could change her perspective on her own relationships.
Jiraiya would also be a great character in this fanfiction. His pervy yet wise nature combined with his knowledge of senjutsu could lead to some really funny and also some very deep moments in the story. He could interact with the characters in High School DxD in a unique way, perhaps teaching them some of his own skills or learning from them as well.
Yuki is also a great choice. Her dual identity as a human raised among vampires gives a lot to work with. You could write about her trying to find her true place in the world. For instance, she might start to question whether she really belongs with the vampires or if she should try to fully embrace her human side. She could also have new relationships with other characters that further explore her identity.
Kirby would be really interesting. His innocent appearance combined with his extremely powerful abilities makes for a great contrast. He could be the source of both humor and unexpected plot twists. For example, when he first meets Naruto, Naruto might try to offer him ramen, not knowing Kirby's preference for food is more about swallowing enemies. And Kirby's reactions to the different jutsu in the Naruto world could be really fun to write about.
Naruto himself would be really interesting. Imagine him trying to understand and adapt to the samurai way of life. His energetic and determined personality would bring a lot of humor and action as he clashes with the more traditional samurai values at first, but then finds common ground.
Naruto himself would be very interesting. His energetic and determined personality would make for great adventures in the GTA world. He would probably approach the chaos and crime of GTA with his usual enthusiasm, trying to bring justice in his own ninja - way. His ability to make friends easily could also lead to some interesting alliances with GTA characters.
Sakura from Naruto could be an interesting choice too. In a fanfiction, she could travel to the Kaze no Stigma world and study their medical magic, which could be different from what she knows in the Naruto world. This could lead to her developing new skills and having new adventures.
I think Naruto himself would be really interesting. His positive attitude and strong will would contrast greatly with the cynical world of The Boys.
I think Alex Mercer would be really interesting. He has such unique and powerful abilities in the Prototype world. In a crossover with Naruto, seeing how he would interact with the ninja and their chakra - based powers would be fascinating. He could either be an ally or a potential threat depending on how the story unfolds.