Well, one possible plotline could be about the dragons' struggle for survival in a harsh winter. Maybe they have to find new sources of food and shelter.
Perhaps there's a plotline where the dragons form alliances with other magical creatures to face a common enemy during the winter. This could involve complex relationships and negotiations among different species.
Another interesting plotline might be a young dragon's journey of self - discovery during the winter. It could face challenges that force it to learn about its own powers and place in the dragon world. For example, it might encounter an ancient prophecy that it is destined to fulfill, which adds a sense of purpose and adventure to its journey.
One interesting plotline could be the characters facing a new, powerful Grimm threat as winter arrives. They might have to adapt their fighting styles and strategies to deal with the cold environment that comes with winter and the challenges it poses to their abilities.
One possible interesting plotline could be the unique ways in which the characters in the North approach dragon - killing. Maybe they use ancient and forgotten techniques passed down through generations. Another could be the moral dilemmas they face when dealing with these majestic yet dangerous creatures.
Another possible plotline is the discovery of a new breed of dragon that has the combined powers of fire and ice. This causes a stir among the existing dragon communities as they try to figure out what this new dragon means for their future. There could be a race among different groups to either control or protect this new dragon, leading to a series of adventures and challenges.
One interesting plotline could be the rebirth of a powerful dragon with amnesia, having to rediscover its powers and past. Another might involve the dragon's new relationships with other mythical creatures in the fanfiction world.
One interesting plotline could be Natsu's struggle to fit in with human society after being raised by dragons. He might have different values and ways of doing things that clash with humans.
One interesting plotline could be the discovery of a new type of dragon with unique abilities. For example, a dragon that can change its color to blend into different environments, which adds a new layer of strategy in battles and hiding from enemies.
One interesting plotline could be Daenerys using her dragons to discover a hidden, ancient civilization. The dragons might lead her to a lost city filled with magic and secrets.
In some 'Game of Thrones Winter King fanfiction', there might be a plot where the Winter King discovers a long - lost magic that can change the course of the war for the Iron Throne. This could involve him delving into ancient ruins or seeking the advice of reclusive wizards.
There could be a powerful elder dragon as one of the main characters. This dragon might have a lot of wisdom and be a guiding force for the younger dragons.
One possible plotline could be Hiccup's journey to earn the respect of the dragons and prove herself worthy of being their queen. Maybe she has to face challenges like rival dragon riders or ancient dragon prophecies.