Yes, there are some out there. You can try looking on fanfic websites like Archive of Our Own. Just search for 'Shadow Bonnie x Shadow Freddy' in the search bar, and you might find some interesting stories that people have written.
In 'Shadow Bonnie x Shadow Freddy fanfic', a recurring theme is the power dynamic between them. Some fanfics show Shadow Freddy as the more dominant one, while others may flip it. Additionally, themes of redemption can be found. Despite their somewhat menacing appearances, some stories explore the idea that they can find a path to redemption through their relationship. And of course, the theme of the unknown is always there. Their shadowy nature leaves a lot of room for speculation, and fanfics often take advantage of this to create suspenseful and thought - provoking stories.
The mystery around their characters makes it interesting. Shadow Freddy and Shadow Bonnie are both quite enigmatic in the original lore. A fanfic can explore their relationship, whether it's a friendship or something more, in ways the official story doesn't.
There's a 'Shadow Freddy x Shadow Bonnie fanfic' called 'Shadows United'. In this fic, the author really focuses on their shared experiences in the haunted place. It has some great descriptions of their interactions, like how they communicate without words, which adds to the mystery and allure of their relationship.
Classic 'the shadow' novels often have an element of mystery. There is usually something hidden or unknown that lurks in the background, like a shadow. For example, in 'The Shadow over Innsmouth', the mystery of the strange sea - creatures and the town's secrets create that shadowy atmosphere.
One classic 'the shadow' novel could be 'The Shadow over Innsmouth' by H.P. Lovecraft. It's a great example as it weaves a tale of horror and mystery, with the eponymous 'shadow' of the strange and menacing events in Innsmouth.
Freddy in fanfiction sometimes has a sense of humor. He can crack jokes to lighten the mood, especially when they are in a tense situation. Bonnie is often portrayed as intelligent. He might be the one who comes up with clever plans. In a story where they need to outwit an enemy, Bonnie's intelligence shines through. Also, their loyalty to each other is a common characteristic. No matter what happens, they always have each other's backs.
Dr. Eggman might also be a part of the story. He's the main antagonist in the Sonic series. His evil plans could be the catalyst for Sonic and Shadow's encounter. Whether it's stealing chaos emeralds or creating some new doomsday device, Eggman's actions could force Sonic and Shadow to interact and either fight against or alongside each other.
In such a fanfiction, they might start as rivals. Sonic, with his speed and carefree attitude, could initially clash with Shadow's more brooding and serious nature. For example, they could compete in a race across a fantastical landscape filled with loops and obstacles. Sonic would be in it for the thrill, while Shadow might see it as a test of his own abilities.
Friendship is a common theme. They often start as strangers or even foes and then develop a friendship. Another theme is adventure, as they explore the pizzeria together.