Well, in some izuku growth quirk fanfiction, a great plotline is when Izuku has to hide the full extent of his growth quirk. Maybe because it's too powerful and he doesn't want to attract the wrong kind of attention. This could lead to some really tense moments where he has to use it subtly to save the day without revealing his true power. Also, there could be a plotline where his growth quirk is tied to his emotions, so he has to learn to control his feelings to master his quirk.
One interesting plotline could be Izuku using his voice quirk to communicate with animals. Since many animals respond to different frequencies and tones, his voice quirk might allow him to understand and direct them. For example, he could use it to get a flock of birds to create distractions during a villain attack. Another plotline might involve Izuku using his voice quirk to soothe people in distress. His voice could have a calming effect, which would be useful in rescue situations or when dealing with panicked civilians. And a third plotline could be Izuku having to train his voice quirk in secret because it's considered too dangerous or unpredictable, and he has to find unique ways to control and develop it without getting caught by the wrong people.
One interesting plotline could be Izuku using his Pokemon - like quirk to battle villains in a unique way. For example, he might summon Pokemon - inspired creatures with different powers to counter various villain attacks.
Bakugo is often paired with Izuku. Their complex relationship from the original series can be further explored in fanfiction with Izuku's growth quirk. All Might is also a common character paired with Izuku. He could play a role in guiding Izuku to control and develop his growth quirk. Ochaco is another one. She might be involved in stories where Izuku's growth quirk affects his relationships, especially romantic ones.
One possible plotline could be that Izuku has a quirk that is initially very weak but has an unexpected growth potential. He might struggle to control it at first, causing some chaos at school. For example, if his quirk was related to telekinesis but he could only move small objects, and every time he got excited, things would start flying around randomly. His friends would have to help him learn to control it, and this would strengthen their bonds. Another plotline could involve a quirk that is considered 'evil' in society, like a quirk that can manipulate shadows in a way that seems menacing. Izuku would then have to prove that he can use it for good, facing discrimination and misunderstanding along the way.
There are also fanfictions where Izuku's quirk has a hidden aspect. Maybe his connection to One For All unlocks memories or abilities from the previous users in a more profound way. For instance, he might be able to access the combat knowledge of the past users directly, almost like having an in - built combat instructor guiding his every move.
One interesting concept could be Izuku having the power to manipulate cosmic energy for teleportation across galaxies. This would open up new adventures and challenges for him.
One interesting story could be where Izuku's portal quirk allows him to access different dimensions filled with unique heroes and villains. He might use this to learn new combat techniques.
In some Izuku Pride Quirk fanfictions, his quirk could be linked to the pride of others. So, when he's around people who are proud of themselves or their achievements, his quirk gets stronger. This creates an interesting dynamic where he has to surround himself with positive and confident people to reach his full potential. It also gives room for character development as he learns to inspire pride in others to strengthen himself.
One idea could be a crossover with the "Harry Potter" universe. Izuku could have his own quirk and attend Hogwarts, facing challenges in a magical world while also dealing with his normal quirk - related issues. Maybe his quirk could interact in unexpected ways with magic.
One interesting Izuku chain quirk fanfiction could be about Izuku having a chain quirk that allows him to connect with people's emotions. He uses this quirk to bring together a divided class of heroes - in - training. The chains represent the bonds he forms with his classmates, and he uses these connections to overcome various challenges in the hero academy.