A really cool plot could be the discovery of a new type of quirk that is far more powerful than anything seen before. The next - generation heroes have to figure out how to either control it if they have it, or combat those who do. This could lead to all sorts of power struggles and moral dilemmas within the hero community.
Perhaps a story where the next generation has to deal with a public that is growing distrustful of heroes again, like in the early days of hero society in the original series. They'd have to work hard to regain the public's trust while also fighting villains.
Perhaps the next - generation fanfiction could explore a world where quirks start to disappear suddenly. The children of the heroes must find a way to either stop this or adapt to a world without quirks. They could look into the origin of quirks and in the process, uncover secrets about the first generation of heroes that were long forgotten. This would force them to reevaluate what it means to be a hero in a changing world.
A cool fanfiction concept could be to have a character lose their quirk and then have to find a new way to be a hero. This would show their determination and resourcefulness. Or, you could write about a new villain who has a quirk that specifically targets the heroes' weaknesses, and how the heroes would have to work together to overcome this threat.
One idea could be exploring Tomura's past in more detail. Maybe show his childhood before he became a villain, how he was influenced by All For One. Another could be a story where Tomura tries to redeem himself, which would be a huge twist from his normal villain role.
One idea could be a crossover with 'One Piece'. The heroes from 'boku no hero academia' could end up on the Grand Line and have to deal with pirates while also using their quirks. Another is a crossover with 'Naruto'. Maybe the students of UA could train with the ninja in Konoha, learning new skills and sharing their quirk knowledge. A third could be a crossover with 'Attack on Titan', where the heroes have to face the Titans and figure out how to use their quirks to defeat these huge threats.
In a 'boku no hero academia the gamer fanfiction', the main character could be a transfer student who has a gamer - inspired quirk. They could use this quirk to create strategic plans for hero battles. For instance, they can map out the battlefield in their mind like a game level. They might also be able to recruit other heroes by offering them in - game - like rewards. This would create a whole new dynamic in the relationships between heroes. Additionally, they could use their knowledge of gaming glitches to find weaknesses in villains' defenses.
Another plot could be reincarnating as a student in a different class than the main characters. The protagonist then has to work hard to prove themselves and make their own mark in the hero school, while also interacting with the well - known characters in new and unexpected ways. For example, they might form an alliance with a character who was originally an antagonist in the series.
The children of Deku and Ochaco would be interesting main characters. They could inherit a combination of their parents' quirks and personalities. For example, their child might have Deku's super strength but Ochaco's bubbly and friendly nature.
A plot could revolve around Itsuka Kendo forming an unexpected alliance with a villain. Maybe she realizes that the villain has some redeeming qualities or is being forced into their actions. This would put her in a moral dilemma as she tries to figure out how to handle the situation while still being a hero.
One idea could be that Naruto characters are transported to the My Hero Academia world and have to adapt to the different power system. For example, Naruto might be confused by the concept of Quirks at first but then find similarities to chakra. Another could be a training session where Deku and Naruto train together, with Naruto teaching Deku about his never - give - up attitude.
One idea could be exploring new quirks that emerge in the future. For example, a quirk that allows the user to manipulate time on a small scale, which could add a whole new dynamic to battles and relationships. Another could be about the next generation of heroes facing a new, more powerful villain that the current heroes have unknowingly set the stage for. Maybe a villain who has found a way to nullify all existing quirks.