One more interesting crossover could be Hinata and Raine. Hinata's shy yet strong - willed personality would be an interesting match for Raine's intelligent and somewhat strict character. Hinata could learn more about magic from Raine, while Raine might be intrigued by Hinata's Byakugan and the unique way of seeing the world it offers.
One plot idea could be that Naruto is somehow transported to the world of Tales of Symphonia. He might use his ninja skills to help the characters in their quests. For example, his shadow clone jutsu could be used to confuse enemies during battles. Another idea is that a character from Tales of Symphonia ends up in the Naruto universe and has to adapt to the ninja way of life, like learning to use chakra.
Ladybug and Frisk would be really interesting. Ladybug is a strong superhero, and Frisk is a determined human in the Undertale world. Their meeting could lead to some great character development as they both have a strong sense of justice. Ladybug could learn about Frisk's pacifist ways of dealing with enemies, and Frisk could be inspired by Ladybug's courage.
He could fit as a powerful dark force. His unique abilities like the Rasengan and Sharingan (if he somehow has it in this fanfic) would be very different from the magic and skills in Tales of Symphonia. This would make him a mysterious and feared entity in that world.
I think Kakashi would be very interesting too. His experience and wide range of jutsu would be valuable in a zombie - filled world. He could use his Sharingan to copy any unique abilities the zombies might have and use it against them.
Definitely Naruto and Ichigo. Ichigo has his own set of powers as a Soul Reaper and Naruto has his ninja abilities. Their different personalities and ways of fighting would make for an interesting dynamic. Ichigo is more brooding and Naruto is very energetic, so seeing them interact and work together would be cool.
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.
The interaction between Naruto and Mine would be really interesting. Naruto's positive and determined attitude would contrast with Mine's more serious and sometimes cynical nature. They could have some great conversations where Naruto tries to cheer Mine up or convince her of the power of hope.
Bloom from the Winx Club would be really interesting. She's already a powerful fairy with her dragon fire. Meeting Naruto would be a great opportunity for her to expand her skills. She could learn about Naruto's way of fighting and his sense of loyalty. And her magical powers could also be a great asset in Naruto's world, like when they face enemies with magical abilities.
Naruto and Shrek would be an interesting pairing. They are both very different yet share some common traits. Naruto is full of energy and determination to protect his village, while Shrek just wants to be left alone in his swamp but also has a big heart. Their interactions would be full of humor and also moments of understanding as they come from different worlds but have similar values in a way.
Naruto and Fry would be an interesting pairing. Naruto's energetic and determined nature combined with Fry's laid - back and clueless attitude could create some really funny and heartwarming moments. Another interesting pairing could be Sakura and Leela. Sakura's medical skills and strong - willed personality could contrast and complement Leela's leadership and combat skills.