A story where the OC is a healer who is tasked with fixing Gowther's 'heart' so to speak. Since Gowther is a doll, he has some emotional and psychological aspects that are different. The OC could try different methods, and through this process, they fall in love with each other as they get to know each other on a deeper level.
Another interesting idea is a time - travel based fanfiction. The OC accidentally travels back in time and meets Gowther in his past. This could lead to a lot of drama as the OC tries not to disrupt the timeline while also getting closer to Gowther. They could end up changing small things that have big impacts on their relationship.
Another great crossover could be Gowther in the 'One Piece' universe. Gowther could join the Straw Hat crew. His unique abilities would be quite useful during their adventures. He could use his memory - manipulation powers to deceive their enemies, like when they are facing the Marines or other pirates. And his rather naive nature about emotions could also lead to some comical and heartwarming moments within the crew.
A Gowther x King fanfic could be set in an alternate universe where they are both students in a magic academy. King is popular and well - liked, while Gowther is the quiet loner. They get paired up for a project and at first, King is frustrated with Gowther's lack of emotion. But as they work together, King discovers that Gowther has a depth of knowledge and a hidden heart that he grows to care about.
There might be a fanfiction where Gowther accidentally uses his powers in a way that affects Ban's memories related to a past event. This causes Ban to act in strange ways, and Gowther has to figure out how to reverse it. It delves into their relationship in a different way, showing how Gowther's power can both cause and solve problems between them.
Archive of Our Own (AO3) is a great place to start. It has a large collection of fanfiction from various fandoms, including Seven Deadly Sins where Gowther is from. You can use the search function to specifically look for Gowther x OC stories. There are often tags that can help you narrow down your search, like the genre of the story or the rating.
Another interesting plot could be that the OC is from another dimension and gets stranded in Gotham. Batman, being the detective he is, tries to figure out how to send the OC back while also dealing with the chaos the OC's presence causes in the city, as their technology or powers are not from this world.
An interesting concept could be an OC who is initially afraid of Digimon but is forced to team up with one. As they journey together, they gradually overcome their fear and develop a deep bond, learning important life lessons along the way.
One idea could be an OC who is a trainer from a far - off land coming to the well - known Pokemon regions to compete in the Pokemon League. Their unique training methods and the relationships they form with their Pokemon can be a great focus. For example, their OC might use music to soothe and train their Pokemon, which is something not commonly seen in the regular Pokemon world.
One idea could be an OC who is a scientist accidentally stumbles upon a Predator's hunting ground. The OC has to use their wits and scientific knowledge to survive and even form an unlikely alliance with the Predator. Maybe the OC discovers a way to communicate with the Predator through some sort of energy signal, which intrigues the Predator enough to not kill them right away.
One idea could be that the OC is a kind - hearted soul who gets lost in the forest on Krampusnacht. Krampus, instead of punishing them right away, is intrigued by their innocence. He decides to follow the OC and protect them from other dark forces in the forest while also teaching them about the balance of good and evil.
One idea could be that the OC is a powerful warrior from a different dimension. They meet Kefla during a universal tournament. Their powers are so different yet complementary that they start to train together, and gradually a deep bond forms between them as they learn from each other's fighting styles.