The 'forbidden love' trope is also common. Maybe an alpha from the hero side falls in love with an omega from the villain side. Their different social standings and the nature of the ABO society make their relationship a difficult and exciting one to explore in fanfic.
One popular trope is the 'alpha hero saves omega'. For example, in many fanfics, an alpha hero from BNHA like Bakugo might save an omega character from a dangerous situation. This plays on the traditional hero - damsel in distress dynamic but with the ABO twist.
One common trope is the power dynamic. In abo fanfic, alphas are often depicted as having more power, both socially and physically. Another is the mating bond. It's a central concept where the connection between characters, especially an alpha and an omega, is intense and often drives the plot. For example, in some fanfics, the mating bond might be a source of conflict if it goes against the characters' prior relationships or their own self - identity.
One popular trope is the 'Power Struggle'. In bnha oc fanfiction, the original characters often face challenges in controlling or coming to terms with their unique powers. Another is the 'Friendship Overcoming All'. OCs form deep bonds with the canon characters and these friendships help them get through tough situations. Also, the 'Hidden Heritage' trope is common, where the OC discovers they have a special lineage or background that gives them an edge in the hero world.
One popular trope is the 'transfer student' where a character from another series enrolls in U.A. High. For example, a character from Naruto might show up with their unique abilities, creating interesting interactions with the BNHA characters. Another is the 'power swap' trope, where BNHA characters get the powers of characters from a different universe and have to adapt. And the 'alternate universe' trope is also common, like a world where heroes and villains have different alignments or the BNHA world has a different social structure due to the influence of another fictional world.
FanFiction.net also has a good number of BNHA ABO fanfics. It has been around for a long time and has a diverse range of stories. However, the search function might not be as precise as AO3, but with a bit of browsing, you can find some interesting reads.
One popular BTS ABO fanfic could be 'Mate' where it explores unique relationships among the members in the ABO universe. It often delves into themes of loyalty and love.
ABO fanfic is popular because it offers a unique and imaginative world with diverse relationship dynamics and character possibilities.
Some popular bnha fanfic themes include alternate universes, like where the characters have different quirks or are in a different time period. Another common theme is character relationships, such as exploring friendships in more depth or creating romantic pairings that may not be as prominent in the original story. Also, there are fanfics that focus on the backstories of the characters, delving deeper into what made them who they are in the BNHA world.
One popular trope is 'enemies to lovers'. In many fanfics, two characters who initially dislike each other gradually fall in love. Another is 'the chosen one' trope, where a character is singled out for a special mission or power. 'Soulmate' trope is also common, where characters are fated to be together in some way.
One popular concept is the backstories of the villains. Many fanfics explore what led them to become villains in the first place. For example, they might delve into Tomura Shigaraki's past and how he was influenced by All For One. Another concept is villain redemption arcs. Writers like to imagine if villains could be redeemed and how they would go about it in the context of the BNHA world. And then there's the idea of villain alliances and power struggles within their ranks, which can make for very interesting and complex plotlines.
One popular bnha villin fanfic could be those that explore the backstories of the villains in depth. For example, a fanfic might focus on how Tomura Shigaraki became the way he is, delving into his past traumas and how they shaped his villainous ideology. Another could be about the League of Villains' internal dynamics, like the relationships between different members such as Dabi and Toga. There are also fanfics that create alternate universes where the villains have different goals or are redeemed in some way.