In a fanfiction, the Avatar State of Aang could be used in a more creative way. For example, Aang accidentally enters the Avatar State during a cultural festival. His friends are initially worried, but then they realize that in this state, Aang can communicate with the spirits present at the festival in a unique way. He learns secrets about the spirits and their connection to the human world, which he then uses to strengthen the bond between the two realms when he's out of the Avatar State.
One common theme is power control. Aang often has to learn how to handle the immense power of the Avatar State without losing himself. For example, in many fanfictions, he struggles with the sudden influx of energy and the potential for destruction it holds.
Another fanfiction could explore the challenges they face during Katara's pregnancy. Since Aang is the Avatar, he has many responsibilities. There could be a conflict where he has to leave for an important mission, but he doesn't want to leave Katara alone. Katara, being strong - willed, tells him to go and fulfill his duties. In his absence, she discovers new water - bending techniques related to pregnancy and childbirth, which she plans to teach other women in their community later.
Well, 'The Mystery of Aang's Avatar State' is also a good one. In this fanfiction, Aang discovers some long - forgotten secrets about the Avatar State. It has a lot of character development for Aang as he explores the true nature of this powerful state and how it can be used for the greater good.
A good plot twist could be that while in the Avatar State, Aang is possessed by an ancient and malevolent spirit. His friends have to find a way to break the possession without harming Aang. This would create a lot of tension and force them to seek help from unlikely sources, like an old hermit who knows ancient spirit - binding techniques.
One idea could be a crossover where Ben 10's Omnitrix malfunctions near Avatar Aang's world. Ben and Aang team up to face a new threat that is causing chaos in both their realms. Maybe some of Ben's alien forms have unexpected interactions with the bending abilities in the Avatar world.
One idea could be Naruto somehow accessing an Avatar State similar to the one in 'Avatar: The Last Airbender'. Maybe he discovers an ancient jutsu that gives him this power. He could use it to defeat a powerful new enemy that is immune to normal ninjutsu.
One common plot idea is Aang and Katara facing challenges in their relationship due to their different cultural backgrounds. For example, Aang being an Air Nomad and Katara a Water Tribe member.
One plot idea could be a story where Aang and Katara have to face a new threat together that specifically targets their relationship. Maybe a dark spirit tries to create misunderstandings between them by making Aang see false visions of Katara being unfaithful and Katara seeing Aang as being too controlling. They then have to work through these false impressions and reaffirm their love for each other.
Yes, there are quite a few interesting 'Avatar Aang and Katara' fanfictions out there. You can start by looking on popular fanfiction websites like Archive of Our Own. Some fanfictions explore their relationship further after the events of the show, delving into their daily lives and how they grow together.
Well, a common theme in fanfiction is their romantic adventures. Fanfic writers love to imagine Aang and Katara going on secret dates to beautiful, hidden places. These could be secluded islands or magical caves. Their relationship in fanfiction can also be a bit more complex than in the original series. There could be misunderstandings due to their different upbringings. Aang being the last Airbender with a more carefree nature at times, and Katara being a strong - willed Water Tribe girl.