Well, a big theme is friendship. Just like in the shows, fanfictions often show the strong bonds between characters. For example, how Korra's friends support her through her toughest times, or how Aang's group of friends were crucial to his journey. Another common theme is the fight against evil. Fanwriters like to create new villains or expand on the existing ones from the shows. They'll write about how the heroes, using their bending skills and wits, battle against these threats. Also, there's the theme of cultural exploration. Since both shows have richly - detailed cultures for each nation, fanfictions might go deeper into things like the traditions of the Air Nomads or the architecture of the Earth Kingdom.
In many fanfictions, the theme of redemption is quite prevalent. This could be for characters who were antagonists in the original shows or new characters created by the writer. There's also the theme of legacy. How Aang's legacy affects Korra and the world she lives in is often explored. Additionally, love and romance are common themes. We see different pairings, like Korra and Asami in 'The Legend of Korra' fanfiction, and Aang and Katara in 'Avatar: The Last Airbender' fanfiction. Writers will develop these relationships, showing the characters' emotional growth and the challenges they face in their love lives.
One common theme is the exploration of different bending abilities. Writers often come up with new ways of using bending or create characters with unique bending combinations. Another theme is the relationship between different nations. In fanfiction, we might see more in - depth exploration of how the Water Tribes, Earth Kingdom, Fire Nation and Air Nomads interact. And of course, there's the theme of the Avatar's journey. Whether it's Aang or Korra, fanfics often expand on their growth, challenges and how they balance their spiritual and worldly responsibilities.