Perhaps a Garou OC that is a half - human, half - Garou hybrid. This character could struggle with their dual nature, trying to fit in both the human society and the Garou community. They might have to hide their true form from humans while also trying to prove themselves to the more traditional Garou.
One idea could be a Garou OC who is a lone wolf, not part of any pack, and has to survive in a world full of both human and supernatural threats. They could have unique powers like the ability to blend into shadows, which helps them in their solitary existence.
Another option is a crossover with a post - apocalyptic world. The garou's survival instincts and combat abilities would be well - suited for this harsh environment. It could either be a lone wolf trying to survive or join a group of survivors, bringing its own set of skills and challenges to the group.
One idea could be exploring Garou's past more in - depth. Maybe show his childhood and what led him to become the way he is. Another could be a story where Garou has to team up with Saitama for some strange reason, like an even more powerful enemy emerging. Or perhaps a fanfiction where Garou tries to train under Saitama to become stronger in a different way than his usual self - taught methods.
One idea could be that they start off as rivals but are forced to team up against a common, even more powerful enemy. As they fight side by side, they gradually gain respect for each other's fighting abilities.
Another plot could involve a crossover with a different anime universe through a strange portal. For example, if he entered the world of My Hero Academia. Garou could initially try to assert his dominance but quickly realizes that the quirks in that world are different from his martial arts skills. He might then start to learn about these new powers and how to adapt, all while causing chaos and also forming unexpected alliances.
One idea could be a story where Garou and Metal Bat are forced to team up against a common enemy stronger than they've ever faced. They start off hating each other but gradually learn to respect each other's fighting styles.
I'm not sure specifically which ones are the most popular. However, you can start by looking on fanfiction platforms like Archive of Our Own or FanFiction.net. Search for 'garou' and then filter through the results to find those related to the 'big breasted oc' aspect.
One idea could be creating an OC who has a unique power related to time manipulation. They could be from a different dimension and end up in the Avengers' world. Another idea is an OC who is a master of ancient magic and teams up with Doctor Strange within the Avengers group. Maybe an OC that is a super - intelligent android created by a villain but has a change of heart and joins the Avengers.
You could create an OC for your Persona OC fanfiction who is an artist. This artist OC could use their art as a way to understand and even manipulate the Metaverse. For example, they might draw scenes from the Metaverse that give clues about upcoming events or hidden locations. Their art could also be a form of therapy for other characters who are struggling with their dual lives in the real world and the Metaverse.
Perhaps an OC who is a half - human, half - beast creature. This OC could struggle with acceptance in both the human and beast - kin societies. They end up meeting the main characters during their adventures and learn to embrace their unique identity with the help of the group, while also adding their own combat skills, which are a blend of human strategy and beast - like strength, to the team.
One idea could be to explore the Riddler's origin story from the perspective of your original character (OC). Maybe your OC is a detective trying to solve the mystery of the Riddler's first crime spree. Another idea is to have your OC be a sidekick of the Riddler, either willingly or by being forced into it. They could then have a complex relationship where the OC tries to influence the Riddler's actions for better or worse.