In a more adventurous 'Black diamond in white crown story', a group of thieves might be after the white crown with the black diamond. They plan an elaborate heist to steal it from a heavily guarded museum. The black diamond in the white crown is so valuable that it could make them rich beyond their wildest dreams.
Since I don't know the specific 'yellow x white diamond fanfic', I can't say for sure about its plot. It could potentially be about the relationship between two entities named yellow and white diamond, perhaps their adventures, conflicts, or how they interact with other elements in the story's universe.
The untold story could be about their origin. Maybe the diamond crown was once worn by a forgotten queen and the black diamond has some sort of mysterious power. It could also be about how they were lost and found throughout history.
One common theme is their relationship dynamic. Given their positions in the Diamond Authority, many fanfictions explore how they interact with each other, whether it's in a power - struggle sense or a more collaborative way.
Emotional exploration is quite common. Since they are complex characters, fics might look at their hidden emotions, like love, envy, or respect. For example, a fic could show how they struggle to understand their feelings for each other. Friendship or a deeper relationship is also a theme that comes up a lot in these fics.
In 'pink diamond x yellow diamond fanfic', a common theme is the concept of change. How they change over time, either due to external factors or because of their relationship with each other. For example, yellow diamond might become more empathetic because of pink diamond, or vice versa. Another theme is the idea of legacy. Since they are diamonds, their actions and relationships can have a significant impact on their legacy, and this is often explored in fanfics.
Steven is often paired with Black Diamond in fanfiction. Their interactions can be really interesting as Steven has his unique way of approaching Gems and his powers. He might try to understand Black Diamond or even persuade her to change her ways if she's portrayed as a more antagonistic figure.
Sorry, I'm not familiar with a particular 'yellow x white diamond fanfic'. However, if these are unique characters or concepts within a certain fandom, start by looking at the official websites or forums dedicated to that fandom. Fans there might be able to point you in the right direction. Also, social media groups related to the fandom can be a great place to ask for recommendations.
There's also the 'secret relationship' trope. Considering their status in the Diamond Authority, a relationship between them might have to be kept a secret at first. Fanfictions might explore the challenges and thrills of keeping such a relationship hidden from the other Diamonds and the rest of the Gem society.
You can try searching on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms. Just type in 'Yellow Diamond x Blue Diamond' in the search bar, and it will show you relevant stories.