You could write a 'little hero academia fanfiction' where the heroes have to face a new type of villain that is immune to most quirks. This would force them to rely on their wits and teamwork more than ever. Also, a story about the teachers' early days as heroes and how they trained would be really cool. It could show how they developed their teaching methods based on their own experiences.
A fun fanfiction could be about a school event at U.A. that goes horribly wrong. Like a sports festival where a villain attacks in the middle and the students have to protect the spectators while still competing. Or you could do a story where one of the characters loses their quirk and has to find a new way to be a hero, exploring themes of identity and perseverance.
One idea could be a crossover where the students from Little Witch Academia visit UA High. They could participate in a joint training exercise. The witches could use their magic in creative ways during combat scenarios, while the heroes-in-training show off their quirks. It would be a fun mix of different powers and personalities.
Well, you could focus on the relationships between the characters. Write a fanfiction about a friendship that forms between two characters who initially didn't like each other. For instance, Bakugo and Midoriya could have a different kind of relationship where they become more like brothers through a series of events that force them to rely on each other. Or you could write about the teachers' lives outside of teaching at the academy. What do they do in their free time? What kind of challenges do they face that the students don't know about? You could also write a story where a new villain emerges with a quirk that is completely unexpected and throws the whole hero society into chaos.
A fanfiction focusing on the family lives of the characters can be interesting. Like, how does Bakugo's family interact when he's not around? Or what was Midoriya's father really like? By delving into these aspects, you can add more depth to the existing characters and show a different side of them that the original story might not have fully explored.
How about a fanfiction where the villains and heroes have to team up? There could be a greater threat, like an alien invasion or a powerful quirk - user who is out to destroy the entire world. The heroes and villains realize that they can't defeat this threat alone, so they put aside their differences. This would lead to some really interesting character interactions, like Bakugo having to work with Shigaraki and both of them learning to respect each other's skills despite their opposing natures.
In 'hero academia sludge fanfiction', you might consider a story where the sludge is actually a misunderstood entity. It was once a normal substance but got corrupted by some evil force. A hero could try to purify the sludge instead of just fighting it. They might have to go on a quest to find the source of the corruption and in the process, learn more about the true nature of the sludge.
A cool concept for My Hero Academia fanfiction is to have a time - travel plot. A character could go back in time and change a significant event in the My Hero Academia world. This could lead to a completely different storyline. Or you could write a story centered around a villain redemption arc. For instance, giving a more in - depth look at how a villain like Shigaraki could potentially be redeemed and how the heroes would react to that. Additionally, fanfiction about a tournament between different hero agencies could be really exciting.
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.
An interesting plot could involve an anti - hero who has a hidden agenda that is not entirely evil but also not in line with the traditional hero goals. Maybe they are trying to expose a corrupt part of the hero society from within. They could form alliances with some villains who also have a vendetta against the corrupt elements. This would create a complex web of relationships and moral dilemmas.
One plot idea could be a villain who is secretly a double agent, working for the heroes all along. They infiltrate the villain group and gather information. Another idea is a hero who loses their quirk and has to rely on their wits and combat skills alone, like Batman in the DC universe. And a villain - hero team - up to face a greater threat that neither can handle alone.
One idea could be exploring Tomura's backstory in more detail. Maybe show his life before he became a villain, his family situation, and what led him to the path of destruction. Another could be a 'what if' scenario, like what if Tomura was redeemed and joined the heroes. He could use his knowledge of the villains to help the heroes take down other threats.