One possible story could be Izuku proving himself in combat training without a quirk. He could use his intelligence and strategic thinking to outwit his classmates with quirks. For example, he might study their weaknesses in advance and set up elaborate traps during the training exercises.
One great fanfic in this genre is 'Quirkless in a Quirked World'. It really delves into how Izuku, being quirkless like Saitama in OPM (in the sense of starting from a disadvantaged state), overcomes challenges. The story shows his determination and how he adapts Saitama - like training methods to become a great hero in the My Hero Academia universe.
Izuku could develop his own unique fighting style. He combines his knowledge of hero strategies and his physical abilities. Maybe he invents gadgets like Batman, which give him an edge in battles against quirk - users. This would make him stand out as a badass hero in the fanfiction world.
A quirkless vigilante in My Hero Academia fanfiction would likely have a very different origin story compared to the typical hero. They could have been bullied or discriminated against because of their lack of a quirk. This would fuel their desire to prove themselves. They might start small, like stopping petty crimes in their neighborhood. As they gain more experience and confidence, they could take on bigger threats. Their lack of a quirk would also make them more relatable to the readers, as most of us are 'quirkless' in the real world. And their journey from being an unnoticed figure to a respected vigilante would be a great story arc.
One great Izuku quirkless fanfiction is 'A Different Path'. It shows Izuku finding his own way to be a hero without a quirk through sheer determination and intelligence. He uses his knowledge of hero strategies and martial arts to hold his own against quirk - users.
The quirkless Izuku in fanfiction with OPM elements is a different beast compared to his canon self. Canon Izuku is full of hope and admiration for heroes. In fanfic, he may start off the same but as he trains like Saitama, he could become more focused on his own power and less on the hero image. His fighting style might also be more straightforward and brutal, like Saitama's. He might not care as much about the flashy moves and hero rankings, but more about being able to defeat any villain in his path.
One popular fanfiction concept could be Deku proving his worth without a quirk in the Bakudeku relationship. Maybe he uses his intelligence and strategic thinking to assist Bakugo in battles. For example, he could analyze opponents' weaknesses and come up with battle plans that Bakugo can execute. This would show that even without a quirk, Deku is an important part of their duo.
One great izuku quirkless fanfic is 'A Quirkless Hero's Ascent'. It shows Izuku's journey without a quirk in a really unique way, with him relying on his intelligence and sheer determination. Another is 'Quirkless but Unstoppable'. This one focuses on Izuku training in secret and developing skills that even those with quirks envy.
One interesting quirkless oc fanfiction could be about an ordinary person in a world of quirks who uses their wits and determination to outsmart villains. For example, they might study the weaknesses of quirk - using opponents and use strategic planning to achieve victory.