A common theme is the underdog story. Deku, being quirkless, is the ultimate underdog. He has to fight against the odds and the prejudice of a world that values quirks highly. This makes for a very compelling story as he overcomes these obstacles, often with Bakugo by his side or as his motivation.
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 common theme is the exploration of the alpha - omega relationship between Bakugo and Midoriya. It often involves power dynamics, with Bakugo's alpha nature sometimes clashing with Midoriya's omega traits.
Perhaps Deku discovers a dark secret about the origin of quirks and decides that the world would be better off without them. So, he starts a villainous campaign to eradicate quirks. He could form an alliance with other outcasts who have been mistreated due to their lack of quirks or abnormal quirks.
Love and friendship are also big themes. Through time travel, Bakugo and Deku might realize how much they actually care about each other. In some fanfictions, their friendship deepens as they face challenges together in the past. It could also lead to a romantic relationship in some stories, as they see each other in a new light and understand each other better.
In fanfiction, a quirkless Deku often has to rely more on his wits. Canon Deku got One For All, but in fanfic, he has to find other ways to be strong. For example, he might study different fighting styles more intensively.
Often, the theme of acceptance is strong. Izuku has to deal with a world that sometimes doesn't accept quirkless individuals as heroes. Jirou can play a role in making him feel accepted and valued. And vice versa, Izuku can accept Jirou for who she is, quirks and all. This mutual acceptance can lead to a deep emotional connection between them, which is often explored in fanfictions.
One great quirkless Deku fanfiction is 'The Quirkless Hero'. In this story, Deku uses his intelligence and intense training to outwit villains. He forms an alliance with other underdog characters. It's really inspiring to see how he overcomes the odds without a quirk.
A frequent theme is the relationship dynamic between Bakugou and Midoriya. In these 'caught' situations, it can either strengthen or test their bond. It might show how they deal with being in a vulnerable position in front of others. Also, the reactions of the onlookers can play a big part in the story, like shock, acceptance, or confusion.
One common theme is rivalry - turned - friendship. Their initial intense rivalry gradually morphs into a deeper bond. Another is growth, both as individuals and in their relationship. They learn from each other and become better heroes as a result.
One common theme could be the exploration of an alternative relationship dynamic between the two characters. It might involve how they navigate their feelings in a different context than the original story.