It's popular because Astrid and Hiccup are such beloved characters. Their relationship in the original story has a lot of potential for further exploration in fanfiction. Fans love to see more of their love story, the tender moments and how they overcome difficulties together.
One popular Astrid loves Hiccup fanfiction is 'Astrid's True Feelings'. It delves deep into Astrid's emotions for Hiccup in a really sweet way. Another good one could be 'Love in Berk' which shows their relationship evolving against the backdrop of their village. There's also 'Astrid's Heart' that focuses on Astrid's internal struggle with her love for Hiccup.
You can try fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms have a large collection of fanfics, and you can search for 'Astrid loves Hiccup' specific ones there.
A more light - hearted plot could be set in a modern - day AU (alternate universe) where Astrid and Hiccup are in high school. Astrid has had a crush on Hiccup for a long time, and the fanfic could detail their journey from being friends to finally admitting their love, with all the typical high - school - related obstacles like popularity differences and peer pressure.
In the fanfiction, perhaps there's a moment when Hiccup gets injured while protecting the village. Astrid stays by his side day and night, taking care of him. She reads to him, makes him his favorite food, and in those quiet days, they realize how much they mean to each other. Their love deepens as they share these tender moments.
It develops gradually. At first, they might be just friends who respect each other's skills. But as they go on more adventures together, they start to notice little things about each other. For example, Hiccup notices how Astrid is always the first to volunteer for dangerous tasks because of her bravery. And Astrid sees how Hiccup's intelligence always gets them out of tough situations.
One possible fanfiction could be about how Hiccup and Astrid deal with the pregnancy. Hiccup might be overprotective, constantly worried about Astrid and the baby. Meanwhile, Astrid could be trying to keep up with her normal Viking duties while also preparing for motherhood. And the lemon element could be a symbol in the story, perhaps it's something Astrid craves during her pregnancy, leading to some humorous or heartwarming scenes between her and Hiccup as he tries to find the perfect lemon for her.
Astrid might initially be in shock. She could just stand there, frozen, unable to believe that Hiccup is really gone. Her eyes wide open and her body trembling as she tries to process what has just happened.
Their relationship might become more equal in some ways. As dragons, they are both facing a new and strange existence, so they have to rely on each other more. They might develop a new understanding of each other's strengths and weaknesses.