Well, in 'Peter Parker x Harry Osborn fanfiction', a common theme is the struggle between good and evil. Harry sometimes has his own inner demons and Peter tries to help him. Also, the theme of self - discovery is often present. As they interact, they both learn more about themselves. For instance, in some fics, Harry discovers new aspects of his personality through his relationship with Peter. And in others, Peter realizes things about himself that he hadn't before. It's all about how their relationship affects their individual growth.
One idea could be a story where Peter tries to protect Harry from the darker aspects of their world. Since Peter has his Spider - Man powers, he could be constantly on guard to keep Harry safe, perhaps from the enemies he made as Spider - Man. For example, a villain might target Harry to get to Peter.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you can easily search for Peter Parker and Harry Osborn stories using the search bar. Just type in their names and you'll get a list of relevant fanfictions.
There's also 'Friendship Forged in Crisis' which is an amazing Peter Parker and Harry Osborn fanfiction. It focuses on a major crisis in the city where they have to rely on each other completely. The story has a lot of action and also some really touching moments between the two characters that really bring out the essence of their friendship.
One common theme is the struggle between friendship and romance. Since they start as friends, the fanfictions often explore how they deal with their new - found romantic feelings. Another theme is loyalty. They are both loyal to each other in different ways, and this loyalty is often tested in these stories.
One great 'Peter Parker x Harry Osborn fanfiction' is 'The Bond Beyond Friendship' which explores their complex relationship as they face various challenges together in a more emotional and in - depth way. Another is 'Shared Secrets' that delves into how they trust each other with things no one else knows.
A fanfic that stands out is 'Harry and Peter: The Unbreakable Bond'. It focuses on how they support each other. There are many scenes where they have heart - to - heart conversations that give a deep insight into their characters. The author does a great job of staying true to the essence of Peter and Harry in the original stories.
Mentorship is also a theme sometimes. Norman, with his experience and knowledge, could potentially be a mentor to Peter in some fanfictions, despite their differences. And there's the theme of secrecy. How they keep their relationship (whatever form it takes) a secret from the rest of the world and the consequences of that secrecy.
One common theme is the struggle between friendship and a deeper romantic/sexual relationship. Given their long - standing friendship in the original stories, fanfiction often explores how that transitions into something more in a yaoi context.
One interesting plot could be that Peter and Harry discover a parallel universe where their roles are reversed. Harry is the one with superpowers in that universe, and Peter is just a normal person. They could explore how this affects their relationship and what they can learn from each other's experiences in their respective universes.