There is also 'Hiccup and Astrid's Adventure'. This one takes them on a journey to a new land. The way it describes their interactions and how they rely on each other is really engaging. The author has a great writing style that makes you feel like you're right there with Hiccup and Astrid during their adventure.
There's also 'The Bond of Hiccup and Astrid'. This fanfiction takes a different approach. It focuses on their love through small, everyday moments. For example, how they train their dragons together and steal glances at each other. It's a very sweet and simple story that really shows their deep connection.
Archive of Our Own (AO3) is also a great place. It has a very inclusive and diverse set of fanfictions. Just search for 'httyd hiccup and astrid' and you'll get a bunch of results. The site also has good tagging systems so you can easily find stories with the elements you like, such as adventure or romance.
Since 'lemon' fanfics are inappropriate, we can talk about common themes in regular Hiccup and Astrid fanfics. One common theme is their partnership in dragon - training and leading Berk. Another is their evolving romantic relationship, from initial attraction to deep love.
You can find it on fanfiction.net. There are a large number of stories dedicated to Astrid and Hiccup there. Just use the search bar and type in their names to start exploring.
Some fanfictions focus on their early days of getting to know each other. For example, a story where Hiccup is trying to teach Astrid more about Toothless and she is initially hesitant but then becomes fascinated, leading to a cute and heart - warming relationship development.
There would be a shift in their dynamic as they prepare for a family. Hiccup, who is used to being adventurous, would have to focus more on home and stability. Astrid, while still strong - willed, would become more nurturing. They would need to find a new balance in their relationship, between their old selves and their new roles as parents - to - be.
Another option is to search on Tumblr. There are often fanfic recs (recommendations) and some users may post their own fanfictions related to this topic. Just type in something like 'HTTYD 2 Hiccup and Astrid kiss fanfiction' in the search bar, and you might get lucky.
The popularity of 'HTTYD Hiccup and Astrid Love' fanfictions is due to the strong base of their relationship in the original series. Fans love to explore more of their love story. They are a very dynamic couple.
The relationship between Hiccup and Astrid is a big draw. Their dynamic in the movie is really interesting, and fans love to explore it further in fanfictions, especially a moment as significant as a kiss.