One popular trope is the 'enemies to lovers' arc. Since they might start off with some differences or even be on opposite sides initially, seeing their relationship develop from that is appealing. Another is the 'hurt/comfort' trope, where one of them gets injured or is in a tough situation and the other helps them out and their bond deepens.
The 'soulmate' trope is also common in Callum x Rayla fanfiction. The idea that they are fated to be together in some way, whether it's through a magical connection or just a strong spiritual bond. And of course, the 'adventure together' trope, where they go on quests or adventures side by side, facing challenges that bring them closer as a couple.
One popular trope is the 'enemies to lovers' kind of story. Since they start off with some differences and mistrust, it's easy to build a story around them growing closer and falling in love. Another is the 'hurt/comfort' trope, where one of them gets injured or is in emotional distress and the other is there to support and heal them.
One popular trope could be the 'first time' trope. It might show their initial hesitation and then the passion that builds up as they make out. Another could be the 'interrupted make - out' where something or someone disturbs them at a crucial moment, adding some comical or tense elements to the story.
It could also be that the lack of such explicit content in the official story makes fans create their own versions. They want to see different sides of Rayla and Callum's relationship, and the 'lemon' fanfiction allows them to do that. Additionally, the creativity of the fanfic authors in developing these stories adds to their appeal.
One popular theme is their relationship growth. Fans love to explore how their bond deepens over time, from initial mistrust to a strong connection. For example, there might be fics that focus on how they support each other during difficult quests.
One popular trope is the 'enemies to lovers' trope. The OC and Rayla could start off on the wrong foot, perhaps having different goals or misunderstandings. But as they are forced to work together, they begin to see the good in each other. Another is the 'fish out of water' trope, where the OC comes from a different background than Rayla, and has to adapt to her world, creating humorous and heartwarming situations along the way.
One great 'Callum x Rayla fanfic' is 'Bond of Magic'. It delves deep into their relationship as they face new magical challenges together. The story beautifully captures their growing bond and how they support each other through tough times.
A great Rayla x Callum fanfic often has well - developed characters. It should stay true to their personalities as seen in the original work. For example, Rayla's loyalty and Callum's determination should be evident in the story.
Another place could be FanFiction.net. However, the tagging system there might not be as precise as AO3. But it still has a large collection of fanfictions. You may need to do some more digging around to find the ones related to Rayla and Callum with the 'lemon' aspect. You can try searching for relevant keywords in the story summaries.
One interesting fanfiction could be about Callum and Rayla's adventures in a new, uncharted part of Xadia. They might discover a lost magic or a new species. Another could be a story where they have to overcome a big misunderstanding between them. For example, Rayla might misinterpret something Callum does in his pursuit of magic and they have to work through it.
You can start by looking on Archive of Our Own (AO3). It has a large collection of fanfics, and you're likely to find many 'Callum x Rayla' ones there. Just use the search function and type in the relevant tags.