Obviously, Laufey and the human are the main characters. Laufey being one of the key figures, and the human, who is his mate, is also central to the story.
In this fanfiction, the plot could center around their love story. It could start with Laufey being initially hesitant about the relationship because of the differences. But as time passes, he realizes the depth of his feelings for the human. They could face external threats together, like enemies who don't want to see a human - Laufey union. Their love could be what gives them the strength to overcome all these obstacles and build a future together.
One possible plot could be that the relationship faces initial resistance from both the Asgardian and human worlds. The human male might have to prove himself worthy to Laufey's people. For example, he could show great courage in protecting Laufey or her kingdom from an outside threat. This would gradually earn him respect and acceptance.
Laufey could start as a very proud and perhaps a bit aloof character. But as she gets closer to the human male, she might become more empathetic. For example, she could start to understand the concept of human mortality and become more protective of her human mate.
Yes, there are likely fanfictions out there with such a plot. Fanfiction writers often explore unique and complex relationships between characters. In the context of Loki and Laufey, it could involve Laufey having some sort of need or desire for Loki, perhaps related to Loki's power or his role in Asgardian or Jotunheim politics. This could lead to an interesting story full of drama, power struggles, and family - related issues.
The plot could revolve around a world where werewolf packs have a strict hierarchy. The main character is mated to the alpha and his beta, which is likely to stir up a lot of emotions and events. There could be jealousy among other pack members, or there could be external threats that force the three of them to work together. This relationship might also be a key to some sort of prophecy or special power within the pack, and the story could be about how they discover and use it.
The fanfiction 'Laufey's Legacy: Loki's Childhood' is quite good. It portrays Laufey as a complex figure in Loki's life. It shows the good and the bad aspects of his parenting. Another notable one is 'Baby Loki's World with Laufey' which creates an immersive world for the two characters. It has a great plot that keeps you engaged as it unfolds the story of their relationship.
Since I haven't read it, I can't say for sure. But based on the title, the main characters are likely to be the one who is mated (presumably a female), the alpha of the pack, and his beta.
One common theme is family drama. Since Laufey is Loki's father, the act of kidnapping creates a lot of tension within the family dynamic. It's about a father - son relationship gone horribly wrong.