Perhaps a plot where the second - gen characters are sent to a special training academy in a different country. There, they face challenges that are culturally different and have to adapt their quirk usage. This could lead to new friendships and rivalries among them.
One idea could be focusing on the children of the main BNHA characters dealing with new villains who have unique powers. They could struggle to live up to their parents' legacies while also finding their own identities.
A cool plot could be that a mysterious organization starts targeting the second - gen characters because of their powerful quirks. The story could follow their attempts to uncover the organization's motives and stop them, all while dealing with the pressures of being the next generation of heroes.
The offspring of Todoroki and Momo could be great main characters. With Todoroki's ice - fire quirk and Momo's creation quirk, their child might have a really unique and powerful combination of abilities. The character could struggle with the high expectations that come from having such powerful parents.
One idea could be that the villains release a powerful virus that turns most of the population into mindless zombies. The heroes have to not only fight the villains but also deal with the zombie horde. Another could be an apocalyptic event that wipes out most of the world's quirks, and the remaining heroes and villains must adapt to this new powerless world.
Maybe in the 'bnha graduation fanfic', there's a competition among the students as part of the graduation. The winner gets a special internship or a chance to work with a top hero. This could lead to intense rivalries and unexpected alliances.
One idea could be a hero with an illusion quirk who uses it to create false distractions during battles. For example, making the villains see an army of heroes when there are really only a few, causing them to waste their attacks and energy.
One idea could be exploring how the characters' relationships change. For example, if Deku was a girl, how would her dynamic with Bakugo be different? Maybe Bakugo would be more protective in a different way. Another plot could focus on how the female versions of the male heroes deal with the challenges in the hero society, like discrimination that might be specific to female heroes. Also, a plot could revolve around a genderbend All Might and how she inspires the new generation of heroes.
A good plot could be a villain being sent to an alternate dimension where they experience a life without quirks. They see how normal people live and cooperate, and this makes them realize that their use of power for evil was wrong. When they return to their own world, they are determined to reform.
One idea could be focusing on the adventures of the next generation at Hogwarts. Maybe they discover a hidden chamber that has been long forgotten, filled with ancient spells and magical artifacts. Another could be a story about the new generation dealing with a new dark wizard threat, but this time they have to use their unique modern - day knowledge combined with magic to defeat it.
Another interesting concept is a chatroom that exists secretly among the villains. They plot their next moves, argue about the best ways to take on the heroes, and maybe even have some internal power struggles. It would be exciting to see their different personalities clash in this virtual space.
One idea could be a crossover with Harry Potter. Imagine Deku attending Hogwarts and learning magic while also trying to control his One For All quirk. He could make friends with Harry and they could share their experiences of being the 'chosen ones'.
Well, you could start with the costumes. In a genderbend fanfic, the female versions of male heroes might have more stylish or practical costumes. For instance, All Might as a woman could have a more form - fitting suit that still represents her power. You could also play with the backstories. Maybe the female - genderbent Deku had to face different kinds of discrimination in a male - dominated hero world. And of course, there could be new romances or different interpretations of existing friendships.