Redemption is also a theme sometimes. Sherry might be written as trying to redeem herself from her past in the organization, and Gin could be a part of that journey in some way. Also, there are fanfictions that focus on the 'what - if' scenarios, like what if they had different roles in the organization or if they had escaped together.
Love - hate relationships are quite prevalent. They have a lot of animosity in the original, but in fanfiction, it can be explored in a more nuanced way. Writers might play with the idea of them having a hidden attraction beneath all the hostility, which makes for an interesting read.
Another common theme is betrayal. Given their complex relationship in the source material, fanfic may delve into how betrayal could play out between Gin and Sherry. It could be Sherry's betrayal of the organization which Gin is a part of, or vice - versa. And this can create a lot of drama and conflict in the fanfic. Also, the theme of redemption can be present. For instance, if one of them has done something wrong, the fanfic might explore their journey towards redemption in relation to their relationship with the other.
One common theme is friendship. Since Naruto values friendship highly in his own story, it's often explored in relation to Sherry Blendy. Another could be discovery, as Sherry discovers the new and strange Naruto world.
One common theme is adventure. Since both Leon and Sherry are characters from the Resident Evil universe which is full of danger and mystery, many fanfictions will have them go on adventures together, fighting against bio - horrors. Another theme is romance, of course. Writers like to explore the relationship between the two, how they might fall in love and support each other.
One common theme is survival. Given their backgrounds in a rather dangerous world, many fanfictions put them in situations where they have to fight for their lives and rely on each other. Another theme is the discovery of self - worth. Through their relationship, both Jake and Sherry often learn more about themselves.
One common theme is the exploration of their different personalities. Gin is often seen as more sly and unpredictable, while Toshiro is more serious and composed. Fanfictions may play with how these personalities clash or complement each other. Another theme could be loyalty, either in a friendship sense or as comrades in some sort of battle or struggle.
Another theme is loyalty. There are stories that show how, despite their differences, both Gin and Matsumoto have a sense of loyalty to their own beliefs or to each other in certain situations. For example, Matsumoto might be loyal to her idea of justice while Gin has his own form of loyalty to his motives, and how these clash or align in the fanfiction.
One common theme is the reaction of their friends and comrades. How will their fellow characters in the original series react to the news? Another theme could be the challenges they face during the pregnancy, like Rangiku's health concerns perhaps.
One common theme is the exploration of an unlikely relationship. Since they are from different groups in the original story, seeing how they interact and form a bond is popular.
One common theme is friendship. Gin and Hotaru might start as friends and their bond grows deeper over time. Another could be adventure, with them facing challenges together.
One common theme is secrecy. Given their characters, their relationship often involves hidden motives and unspoken words.