One interesting fanfiction could be about a crossover where characters from MHA and Naruto meet in a special dimension. For example, Deku could meet Naruto and they learn from each other's unique powers. Another might be a story where the quirks in MHA are introduced to the Naruto universe and how it disrupts the existing power balance. There could also be a fanfic that focuses on a character from MHA being transported to the Naruto world and having to adapt to the ninja way.
The MHA characters' reactions could vary widely. For instance, All Might might see the Naruto fanfiction as a great source of inspiration. He could admire the way the characters in Naruto strive for their goals, just like heroes in their own world. Todoroki might be a bit detached but still interested. He'd analyze how the power systems in Naruto compare to quirks in their world. Mineta would probably be more interested in any fan service - like elements if there were any, but that's not a very positive reaction. Overall, it really depends on each character's personality.
You can start by looking on fanfiction.net. It has a large collection of both MHA and Naruto fanfictions, and you can easily search for crossovers. Archive of Our Own (AO3) is also a great place. It has a more organized tagging system, which makes it easier to find specific types of fanfictions, like those focusing on certain character relationships or plot elements that involve both MHA and Naruto.
One interesting crossover could be the magic system of Harry Potter being introduced to the MHA world. For example, a character from MHA might discover they have magical abilities like a Hogwarts student. Another could be the heroes from MHA having to face off against dark wizards from the Harry Potter universe. It would be a really cool mix of the two different power dynamics.
A lot of MHA Kaminari x Jirou fanfictions focus on the idea of mutual understanding. They come from different backgrounds and have different quirks, but through getting to know each other better, they grow closer. There are also themes of jealousy, like when one of them might get a bit jealous if the other is spending too much time with someone else. Also, their shared experiences at UA, like going through tough battles together, are often used as a theme to bring them closer in the stories.
One idea could be that Naruto characters visit the MHA world and have to adapt to the modern society and different power system. For example, Naruto might be intrigued by how quirks work compared to chakra. Another plot could involve villains from both universes teaming up, forcing the heroes from Naruto and MHA to collaborate. They would need to combine their unique fighting styles and powers to defeat the combined threat.
Characters' personalities play a huge role. For example, Dabi, who has a bit of a dark and brooding personality, might be drawn to the more complex and morally grey characters in Naruto fanfiction. He might relate to some of the characters who have had a tough past. In contrast, Ochaco, being a positive and empathetic character, would focus on the emotional parts of the fanfiction, like the friendships and the characters' dreams. And then there's Tokoyami, with his rather mysterious and deep - thinking nature. He'd be delving into the philosophical aspects of Naruto, such as the concept of the ninja way.
One great Naruto MHA fanfic is 'Naruto in the My Hero Academia World'. It's really interesting to see how Naruto's ninja skills translate into the MHA universe with its own set of superpowers. Another good one could be 'MHA meets Naruto: The Crossover'. It often has unique plotlines that combine the best elements of both series.
I think Kakashi and Aizawa would be a great pairing. They are both experienced teachers who are quite laid - back but can be very strict when it comes to training their students. They could exchange teaching methods and stories about their students. Also, Hinata and Ochaco would be an interesting pair. Hinata's shyness and strong - willed nature combined with Ochaco's bubbly and kind personality could lead to some really cute interactions.
I think Harry Potter himself would be very powerful in this crossover. He has the experience of fighting dark wizards and his magic skills. If he was in the MHA world, he could use his magic to enhance his physical abilities like the characters with quirks. His ability to resist the Imperius Curse and his knowledge of defensive magic would give him an edge over many MHA villains.