There could be various interpretations. Maybe Pandora in a Re:Zero fanfic might be depicted with a certain allure or charm that could be misconstrued as related to sex, but often good fanfics would focus more on her character's power and role in the Re:Zero universe rather than sexual aspects.
A Re:Zero fanfic focusing on Pandora without sexual content could also highlight her relationship with other characters like Emilia or Beatrice. Maybe she has some hidden agenda regarding Emilia's ascension to the throne. Or her encounters with Beatrice could be full of mystery and power plays. The fanfic could explore her backstory and how it shapes her actions in the current timeline of the Re:Zero story.
One possible plot could be a story of redemption for Roswaal. Ram could be the key to his change. Maybe he has made some mistakes in the past and Ram helps him see the error of his ways. Through their interactions, Roswaal becomes a better person.
One common theme is the exploration of an unlikely friendship. Since Betty and Subaru are quite different characters, fanfics often focus on how they bridge that gap. For example, Subaru's humanity and Betty's more otherworldly nature can create an interesting dynamic.
The theme of redemption can also be found in some 're zero subaru x elsa fanfic'. If Elsa has done some wrong in the past, Subaru could be the one to help her find redemption. Or, Subaru might be the one who needs to redeem himself in Elsa's eyes. Their relationship then becomes a vehicle for this journey of redemption. And of course, there are often elements of the fantastical, like magic use, different realms, and unique creatures that add to the overall theme of the fanfic.
One interesting plot point could be the combination of Naruto's chakra system with the magic in Re:Zero. For example, how would Naruto's jutsu work in a world where magic like Crusch's exists? Another is the cultural clash. Naruto comes from a ninja village with its own values and Re:Zero has its own set of social norms. How do the characters navigate this difference?
There are fanfics that explore their relationship in a more emotional depth. For example, a story where Subaru has to prove his love to Emilia when she is faced with doubts about his loyalty. This often involves him going on a dangerous quest to retrieve a magical item that can show his true feelings. In these fanfics, the author can really delve into the insecurities and hopes of both characters.
Archive of Our Own (AO3) is also a great place. There are many talented writers who post their 're zero subaru x emilia fanfic' there. The tagging system is quite detailed, which makes it easier to filter and find exactly the kind of story you're interested in.
There's a fanfic named 'Betty and Subaru: An Unlikely Alliance'. In this, it starts with a chance encounter between them. It shows how Subaru gradually earns Betty's trust, which is not easy as she is a rather guarded character. It has some really interesting dialogue exchanges that give depth to their relationship.
One good 're zero crusch x subaru fanfic' story could be one where they go on an adventure together. Maybe they are exploring a new part of the Re:Zero world that has not been fully discovered in the original work. It could involve them facing challenges and relying on each other's strengths.