Yes, there are likely some popular ones. For instance, some fanfictions that explore the relationship between Hiccup and Astrid during the time leading up to HTTYD 2 are quite popular. They might show how their relationship evolves and how they support each other in anticipation of the new threats in the second movie.
There's a fanfiction called 'Into the Unknown with Dragons' that has gained a lot of popularity. It takes the characters from httyd and rtte on a journey to unexplored lands filled with new types of dragons. The story is full of adventure and mystery, which is what attracts a lot of readers. Additionally, 'The Dragon Riders' Redemption' is popular as it delves into the past mistakes of the dragon riders and how they strive to make amends during their further adventures in the rtte - like setting. It has a great mix of action, emotion, and character development.
This is such a unique idea. Firstly, we need to consider that 'httyd' in this context is fictional, but if we imagine it could watch fanfiction. It might react in different ways depending on the type of fanfiction. For instance, if it's a well - written action - packed fanfiction that stays true to the spirit of the original, it might enjoy seeing its world expanded. However, if it's a fanfiction that goes against the core values of the httyd world, it might be a bit shocked or dismayed.
There are fanfictions that focus on the relationships between the characters in Berk while they are watching HTTYD 1. For example, how Hiccup's relationship with his father might change during the viewing experience. These fanfictions often add a new layer of depth to the existing relationships in the HTTYD universe.
Fanfiction.net is also a popular place. Just use the search bar and type in 'Berk Watches HTTYD 1'. However, be aware that the quality can vary a lot on this site.
Fanfictions about watching HTTYD 3 in the past often focus more on the viewer's personal experience and how the movie affected them. Normal HTTYD 3 fanfictions usually center around the events and characters within the movie's universe directly.
Well, in the real world, it's not possible. But if we were to think in a more creative, fictional sense, like in a meta - story where the httyd world intersects with our own digital or written realm in some magical way, then maybe. But generally, no, as it's just a fictional entity without the physical or mental faculties to do such a thing.
Good 'Berk Watches HTTYD 2' fanfiction often stays true to the characters. The personalities of the Berk inhabitants should be recognizable. Also, it should have a clear plot that either expands on the events in the movie or offers a new and interesting take. For example, if it's about how Berk prepares for the dragon battles, it should be detailed and logical.
There probably are. 'How to Train Your Dragon' has a huge and passionate fan base. Fanfiction writers often take the characters, such as Hiccup (from what I think you meant) and other related characters, and create their own stories. So it's very possible that there are works of fanfiction that someone could watch, perhaps in the form of written stories being read aloud or turned into some kind of visual adaptation by fans.
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.
I can't really point you to 'lemon' fanfiction as it usually involves adult - themed or inappropriate content. But in general, Toothless and Stormfly fanfictions that are popular often involve their epic battles side by side or their heartwarming interactions within the dragon - vikings community of Berk.