In a lot of these fanfictions, the theme of unrequited love can play a part. Ruby might develop feelings for someone who doesn't return them, and this causes her emotional distress. Additionally, the theme of being misunderstood is common. People around Ruby may not understand why she's acting a certain way because of her hurt, which just adds to her pain and isolation.
One common theme is isolation. Castiel often feels alone in his pain, whether it's due to his otherworldly nature or the actions of those around him. Another theme is betrayal. He is frequently betrayed in these stories, which causes him deep emotional harm. For example, when his allies turn on him or when he is misled by false friends.
I'm not sure about a specific title right now, but you can try searching on fanfiction platforms like Archive of Our Own. Look for stories tagged with Ruby and 'emotional hurt'. There are likely many great ones there. Usually, in such fanfics, Ruby might face betrayal or loss, which makes for a very emotional read.
Another theme is self - discovery. As they interact in the fanfictions, both Otis and Ruby often learn more about themselves. For example, in some stories, Ruby discovers a more sensitive side of herself through her interactions with Otis.
The theme of self - discovery also pops up a lot. Ruby might be trying to figure out her place in the world outside of being a simple villager, and Belle might be learning more about her own strength and how to use her intelligence in different situations. Fanfictions explore how they grow and change as individuals while still maintaining their relationship.
One common theme is the struggle between Ruby's human side and her vampire nature. This often involves her trying to resist the urge to feed on blood or deal with the newfound powers that come with being a vampire.
A common theme is their friendship development. Writers often explore how they grow closer as they face challenges together. Another theme could be their growth as individuals within the context of their relationship. For example, Ruby's leadership skills might be enhanced by her interactions with Oscar.
One common theme is leadership. Ruby is a team leader in RWBY, and many fanfictions explore how she grows into that role, like dealing with difficult decisions and inspiring her teammates. For example, in some fanfictions, she has to lead her team through a very dangerous mission where every decision matters.
Love is a very common theme. Since Ruby and Sapphire have a strong relationship in the original, fanfictions often explore different aspects of their love, like how they overcome challenges together.
One common theme is adventure. Writers might send Ruby Belle on exciting quests or into unknown lands. Another is friendship, exploring the relationships she has with other characters.
One common theme could be emotional pain. Maybe Arthur has been betrayed by someone close to him, and the fanfiction explores his journey of dealing with that hurt. For example, if a friend he trusted turned out to be a traitor.