One common theme is the 'fish out of water' scenario. Since Stiles is from a world with werewolves and magic, and Steve is from a more 'normal' superhero world at first glance, their interactions can create interesting situations where they learn about each other's worlds.
There's also the theme of heroism. Steve is a well - known hero, and Stiles has his own kind of heroism in the Teen Wolf universe. Fanfictions might explore how they inspire each other to be even better heroes. They could team up to fight a common enemy that combines elements from both of their universes, like a super - powered werewolf or a Hydra agent with magic powers.
Another theme is the power of friendship. They both have strong bonds with their respective friends in their original shows/movies. In the fanfiction, they often form a deep friendship that might turn into something more. For example, they support each other through difficult times, like when Stiles is dealing with the latest supernatural threat or Steve is facing a new enemy.
You can try Archive of Our Own (AO3). It has a vast collection of fanfictions, and you're likely to find some great Stiles Stilinski x Steve Rogers fanfictions there. Just use the search function and type in the relevant tags.
The theme of growth and change is also prevalent. The pregnancy forces both Stiles and the OC to grow up and take on more responsibilities. They have to adapt to their new situation, which can be a source of character development. For example, Stiles might become more serious and focused on building a stable future for his family, while the OC might discover new strengths within herself as she prepares to become a mother.
A prevalent theme is Stiles' self - doubt and how it gets exacerbated when he's hurt. He might question his own worth, especially if he thinks his being hurt is putting his friends in danger. Fanfictions often show his internal struggle as he tries to come to terms with his situation and regain his confidence. Sometimes, his hurt can also be a catalyst for character growth, where he learns to be more self - reliant or better at communicating his feelings.
One common theme is friendship. Often, the female character starts as a friend to Stiles and their relationship evolves from there. Another theme is mystery, as they might solve some supernatural mystery together. For example, in many fanfics, they team up to figure out the latest werewolf or banshee problem in Beacon Hills.
One common theme is the clash of different worlds. For example, when Stiles crosses into a different universe like the Vampire Diaries' world, his normal life from the Teen Wolf universe clashes with the supernatural politics and rules of the new world.
One common theme is reconciliation. Given their differences in the movies, many fanfictions focus on how they can make up and understand each other better. Another theme is friendship development. They start as colleagues in the Avengers and the stories might show how they become true friends. And of course, there are stories about them protecting each other in dangerous situations.
One common theme is self - discovery. Stiles often has to figure out his true feelings and identity in these fanfics. Another theme is acceptance, both from himself and from those around him.
In female Stiles Stilinski fanfic, a prevalent theme is empowerment. The female version of Stiles often has to prove herself in a male - dominated supernatural world. Adaptability is another theme, as she has to adapt to new situations and powers. And of course, loyalty. Her loyalty to her friends and the pack is always a central theme, just like in the original Teen Wolf story. These themes help to shape the character and make the fanfics engaging and relatable.
A common theme is the fish - out - of - water situation for Steve. Since he's from a different era, many fanfics explore how he adapts to modern life with the reader by his side. For example, in some stories, he's confused by modern technology and the reader helps him understand it.
One common theme is love and attraction. Often, the female characters in these fanfictions are attracted to Steve Rogers' noble and heroic qualities. For example, in many stories, a female character might fall in love with Steve as she sees his selfless acts of saving others.