The themes often revolve around family and friendship as well. Peter might see Stiles as part of his pack or family, and that drives his need to protect. Friendship can also develop in a different way as a result of this protection. For example, Stiles might start to rely on Peter in a way he didn't before, and Peter might open up more to Stiles, creating a deeper friendship. There can also be themes of sacrifice, where Peter is willing to put himself in danger to protect Stiles.
A prevalent theme is the idea of redemption. Peter may have had a checkered past, but by protecting Stiles, he is seen in a new, more positive light. Also, the theme of trust is important. Stiles has to learn to trust Peter's protection, and Peter has to earn that trust. In many of these fanfics, they also explore the power dynamics. Peter is usually more powerful in the supernatural sense, but Stiles has his own strengths, and they have to work together within that power structure while Peter protects Stiles.
Well, I'm not sure of the exact titles all the time, but you can try searching on fanfic platforms like Archive of Our Own. Just type in 'Peter protects Stiles' in the search bar. There are likely to be many stories that come up. Some might focus on specific events in the series where Peter steps up to protect Stiles, while others might create new scenarios for their protective relationship.
One common theme is the exploration of their complex relationship. Since they have different personalities and backgrounds in the show, fanfiction often dives into how they interact and influence each other. Another theme is the supernatural elements. Given the nature of the show, stories might involve them facing supernatural threats together or having unique supernatural abilities related to their bond.
A less obvious but still present theme is self - discovery. Both characters are often on a journey of understanding themselves better. In the context of their relationship in fanfiction, this self - discovery can be influenced by their interactions with each other. For example, Peter might learn more about his capacity for good through his friendship with Stiles, and Stiles might discover new aspects of his own abilities or personality when dealing with Peter.
One common theme is the exploration of trust. Given Peter's past actions, Stiles often has to struggle with whether to trust him or not. Another theme is the power dynamic. Peter is usually more powerful in the supernatural sense, but Stiles has his own form of intelligence and strength, and how they balance this is often explored.
One common theme is redemption. Peter often has a checkered past in the series, and in these fanfics, his act of comforting Stiles can be seen as a step towards redemption. Another theme is the power of understanding. Stiles is a complex character, and Peter's ability to understand him and offer comfort shows a deep connection.
Another theme is protection. Peter and Stiles, being mates, feel an intense need to protect each other. This is often shown in the face of various supernatural threats in the fanfiction world.
One common theme is the exploration of new relationships. Since the mpreg is an unexpected situation, it forces Stiles and Peter to re - evaluate their relationship and often leads to a deeper emotional connection. Another theme is the acceptance within the pack or their community. They have to deal with the reactions of others.
One common theme is the exploration of their complex relationship. They often start with some sort of animosity or misunderstanding which then evolves. Another theme is the supernatural elements, as both characters are often involved in a world full of the supernatural.
One common theme is loyalty. Peter's loyalty to Stiles drives his protective actions. He might not show it in the most conventional way, but he is always there for Stiles when it matters. For example, in many fanfictions, he will go against his own pack or other powerful entities to safeguard Stiles.
A very frequent theme is redemption. Peter, especially, has a lot of past wrongs to make up for, and in many fanfictions, his journey towards redemption while interacting with Stiles and Derek is explored. There's also the theme of family. They form an unusual family unit, and how they adapt to that is often a part of the story.