Yes, there are likely some out there. You can start by checking fanfiction websites like Archive of Our Own or FanFiction.net. Just search for 'Pit x Phosphora' and you'll find a variety of stories written by different authors with different takes on their relationship.
One common theme is adventure. They might go on quests together in the fanfics. Another could be friendship development that might turn into something more romantic over time.
Another option could be Tumblr. There are a lot of fan communities on Tumblr that share and discuss fanfiction. You can search for the 'Pit x Phosphora' tag and might come across some great stories, fanart related to the stories, or even discussions about the pairing which could lead you to some good fanfiction sources.
Another option is Archive of Our Own (AO3). It has a large collection of fanfics. The tagging system there is very useful. When you search for 'Phosphora x Pit', you can filter the results according to your preferences, like the length of the story, the rating, etc.
One common theme is the struggle between light and dark. Since Dark Pit represents the darker side and Pit the more angelic side, their relationship often involves them grappling with these opposing forces within themselves and each other. For example, in many fanfictions, they might have to find a balance when using their powers together.
The theme of redemption can also be found. Dark Pit, being the 'darker' version, might go through a journey of redemption with Pit's help. For instance, in some fanfictions, Dark Pit has made some mistakes in the past and Pit is there to guide him towards a better path. This exploration of good and evil within their relationship is really interesting.
One popular 'dark pit x pit' fanfiction might be 'The Bond Beyond Light and Dark'. It explores their complex relationship in a world filled with challenges and self - discovery. The story delves into how their personalities, which are both similar yet different, interact and change as they face various foes together. It also shows their emotional growth and how they come to rely on each other more than they initially thought.
One popular pit x dark pit fanfiction is 'The Bond Beyond the Mirrors'. It delves into their complex relationship and the idea of self - discovery within their connection.
One common theme is the exploration of their relationship, whether it's a deep friendship, a brotherly bond or a complex rivalry. Another theme is their growth as characters, like how they become stronger together.
There's a fanfiction called 'Pit and Dark Pit: United Front'. In this story, they face a powerful common enemy and their bond grows stronger as a result. It's really exciting to read how they work in tandem. Also, 'The Dark to His Light' is a good one which focuses on the contrast and harmony between them.