One common theme is the combination of their hunting/slaying skills. Since both are used to fighting the supernatural, fanfics often explore how they work together to take on bigger threats.
One great Buffy x Dean fanfic is 'Crossing Paths'. It has an interesting plot where Buffy and Dean meet in a world full of supernatural chaos and they have to team up to fight a new, powerful enemy. The story does a great job of capturing the personalities of both characters.
Another theme is the idea of partnership. Fanfics often explore how Buffy and Dean can work together. Given their skills - Buffy's slayer strength and agility, and Dean's hunting knowledge and weaponry expertise - they make a great team. And stories show how they combine their strengths to take on bigger threats.
There's also 'Buffy and Dean: Crossover Destiny'. This fanfic delves deep into the idea of fate bringing Buffy and Dean together. It starts with Dean arriving in Sunnydale on a hunt and accidentally stumbling upon Buffy's territory. Their initial clashes due to different methods soon turn into mutual respect and a budding friendship that could potentially lead to more.
One plot idea could be Buffy and Dean teaming up to fight a new, powerful supernatural threat that neither of their usual worlds has faced before. Maybe a demon that can cross between dimensions easily.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a vast collection of fanfics, and you can easily search for Buffy and Dean fanfic using the search function.
A common theme is the crossover of their two worlds. Since they both deal with the supernatural, fanfictions often explore how the Buffyverse and the Supernatural world can interact. Another theme is the building of a partnership. Given their skills in fighting evil, they usually end up working together in these stories.
I really like 'The Lemon Grove Encounter' in the Buffy x Faith fanfic world. It's set in a unique location and shows how their relationship can be both tense and tender at the same time. The writing style is quite vivid, making it easy to picture the scenes in your head.
One of the main themes is the exploration of power. As Slayers, they both have power, and fanfics often deal with how they handle it, whether they compete or collaborate. Also, self - discovery is a big theme. They both are on a journey to figure out who they are, especially in relation to each other. For example, Faith might be trying to find out if she can be more like Buffy in some good ways, and Buffy might be learning from Faith's more reckless nature at times. It's a complex interplay of identities.
A common theme is self - discovery. The oc often has to figure out their place in the Buffy - filled world, which is full of danger and magic. Another theme is friendship. They form bonds with Buffy and the Scooby Gang, learning to trust and rely on each other.