I'm not sure about the absolute best, but some popular authors in the Glee fanfiction community might be good places to start. You could look for authors who have a high number of views and positive reviews on fanfiction platforms. For example, some authors who have been writing Glee fanfiction for a long time and have a deep understanding of Finn and Rachel's characters are likely to create great stories.
One interesting Finn Hudson and Rachel Berry fanfiction could be where they reunite after a long time apart. Maybe Finn has been traveling and he comes back to find Rachel on the brink of stardom. They rekindle their old feelings and have to navigate their new lives while still holding on to their past love.
One possible plot could be that Rachel and Finn are newlyweds. They find out about the pregnancy unexpectedly. At first, they're scared but then start to get excited. Finn might start working extra hours to save for the baby while Rachel has to deal with her Broadway dreams on hold. They could face some judgment from friends or family who think they're too young, but in the end, they come together stronger, ready to welcome their new family member.
In the fanfiction, Finn could face challenges in his career as he wants to be there for Rachel during the pregnancy. He might have to turn down some offers that require him to be away for long periods. Rachel, on the other hand, may initially think that the pregnancy is the end of her Broadway dreams. However, as time goes on, she could find ways to combine motherhood with her career. For example, she could start a musical project about pregnancy and motherhood, which could attract a whole new audience.
It could be an overzealous security guard. If Rachel was at a high - profile event and the security guard misinterpreted her actions as something threatening or against the rules, he could be the one to call the cops and get her arrested.
It could lead to a major shift in the story and dynamics among the characters. Maybe the other characters would struggle to cope with the loss and it could change the entire tone of the fanfiction.
Often in fanfiction, their relationship is also about growth. They both grow as individuals because of their interactions. Finn might become more open - minded about different types of music and performance styles thanks to Mercedes' influence, and Mercedes might become more confident in her own abilities as a singer and performer with Finn's constant encouragement.
One common theme is friendship. The original characters often start as friends with Finn and through various experiences, their friendship deepens. For example, they might support each other through tough times in the Glee club or at school.
Finn could be involved if the fanfiction wants to explore a relationship with him as the possible father. He was an important part of Rachel's life in the original series, and his reaction to the news would be significant.
There are many possible fanfictions on this topic. One could be where Rachel is bullied for her over - the - top ambitions in the Glee club. Maybe some of the other members are jealous of the attention she gets from the teacher and start to spread rumors about her, which makes her feel isolated.