In some fanfictions, there might be a crossover where the hero academies in both universes interact. Imagine U.A. High students visiting the school in Invincible's world. This could lead to interesting exchanges of training methods and ideas about heroism. Also, characters like All Might and Omni - Man could have some intense philosophical debates about power and responsibility.
You can make it unique by creating a new power system that combines the quirks from My Hero Academia and the powers in Invincible. Maybe there's a way to fuse a quirk like Todoroki's with Mark's Invincible powers to create something entirely new and exciting for the story.
One great 'My Hero Academia' crossover fanfiction is the one where they cross over with 'One Piece'. It combines the unique powers of the 'My Hero Academia' world with the adventurous and diverse world of 'One Piece'. The characters interact in really interesting ways, like Midoriya being amazed by Luffy's Devil Fruit powers and Luffy being intrigued by the concept of Quirks.
One idea could be that Kakashi is somehow transported to the My Hero Academia world. He could become a teacher at UA, using his ninja skills and wisdom to train the students in new and unique ways. His Sharingan would be a very interesting power in the MHA universe.
One idea could be that Godzilla arrives in the My Hero Academia world during a major villain attack. The heroes initially see Godzilla as a threat but soon realize that he is targeting the same villains who are causing environmental destruction. His massive size and power could be a game - changer in the battle.
A great crossover idea is with the Dragon Ball series. The powerful Saiyans could interact with the My Hero Academia characters. Goku could train the students at UA to reach new levels of power. Also, a crossover with the Attack on Titan world would be intense. The heroes would have to deal with Titans in a whole new way and use their quirks in that battle - filled environment.
Here's a simple start for a 'prototype My Hero Academia crossover fanfic': In a world where the quirks of My Hero Academia exist alongside the powers from 'prototype'. Alex Mercer finds himself in the middle of Musutafu city. He's confused by the sight of people with all these strange abilities. Izuku Midoriya spots this strange man and approaches him. Mercer, being the shape - shifter he is, tries to blend in but his lack of knowledge about quirks starts causing some misunderstandings. As they interact, Mercer realizes that these 'quirks' could be a new form of power to study, while Midoriya is both fascinated and a bit scared of Mercer's abilities.
One idea could be a crossover with the Naruto universe. The characters from My Hero Academia could interact with Naruto characters. For example, Deku might learn some new fighting techniques from Naruto. Another idea is a crossover with the Harry Potter world. The students at U.A. could visit Hogwarts and experience magic, while the Hogwarts students could learn about quirks.
In this crossover, the Avengers could learn a lot from the students at U.A. High. For example, Midoriya's determination might inspire Captain America. And the Avengers' high - tech gadgets could be a wonder to the My Hero Academia characters. Maybe Iron Man would be interested in improving Mei Hatsume's inventions.
There are quite a few great crossover fanfictions between Avengers and My Hero Academia. One that stands out involves the Avengers being transported to the My Hero Academia universe. In this story, they have to adapt to the world of quirks while also trying to find a way back home. It's really interesting to see how characters like Iron Man interact with the likes of All Might.