As of the latest chapters, Izuku and Uraraka have shown some mutual interest and closeness, but it's not a definite romantic pairing yet. It's still evolving in the story.
In some fanfictions, new original characters are introduced. These new characters are designed to be a potential threat to Uraraka's relationship with Deku. They might be transfer students with amazing quirks who immediately take an interest in Deku. Uraraka then sees this new character getting close to Deku and becomes jealous, leading to various conflicts and emotional drama in the fanfiction.
In a midoriya x uraraka fanfic, the author might play with the idea of their unspoken feelings. Uraraka's admiration for Midoriya could be delved into deeper, and Midoriya's possible realization of her importance in his life. It could also include some cute moments like when they train together or share a meal, which would add a lot of charm to the story.
Typically, these fanfics often focus on their relationship, whether it's friendship or a budding romance. They usually incorporate elements from the original 'My Hero Academia' universe, like their hero training and the challenges they face at school.