Well, a cool plot could involve Korra having to deal with a strange phenomenon that is causing all the bending elements to mix uncontrollably. This forces her to find a way to restore the balance not just between the four nations but also within the very essence of bending. She might also encounter a mysterious figure from the past who has some secrets about the origin of bending that could help her in this task. And perhaps there could be a sub - plot where her relationships with her friends and family are strained because of the chaos this situation brings.
One idea could be a crossover with another fantasy world where Korra has to learn new bending techniques from that world's magic users. This would bring a fresh dynamic as she struggles to adapt to different power systems.
To create engaging characters in a 'Be the Leaf Legend of Korra Fanfic', give them distinct personalities. For example, a non - bender character who is extremely brave and uses his wits to outsmart benders. Also, make their backstories interesting. Maybe a character was once a bender but lost their ability and is now on a quest to get it back.
An OC could be a descendant of a long - forgotten Avatar. This OC might start having strange dreams or visions that lead them to discover their heritage and their potential power. They then team up with Korra to learn how to control this new - found power and use it for good. Or perhaps an OC who is a master of a new form of bending that combines two existing bending arts in a unique way. For example, a combination of water and earth bending to create a sort of'mud - slinging' technique that can be used both defensively and offensively. Another option is an OC who is a mechanic in Republic City but discovers a way to use their mechanical skills to enhance bending abilities, like creating a device that helps fire - benders focus their heat more precisely.
One idea could be that the reincarnated character has memories of their past life. They could use this knowledge to predict events in the Avatar world. For example, they might know about an upcoming threat and start preparing for it much earlier than anyone else. This could lead to some interesting interactions with Korra and the other characters as they try to convince them of the danger.
One possible plot idea could be a crossover where characters from Naruto and Legend of Korra have to team up to face the Juubi. Maybe the Avatar from Legend of Korra discovers a new power that is linked to the chakra of the Juubi in the Naruto world.
One idea could be a crossover with another popular fantasy world like 'Harry Potter'. Korra could end up at Hogwarts and have to deal with magic in a completely new way. Maybe she'd use her bending to enhance or counter some spells.
One plot idea could be that your OC discovers a long - lost bending technique. This could attract the attention of both good and bad forces. For example, the Red Lotus might want to use it for their own purposes, while Korra and her friends would try to protect it. Another idea is that your OC is an ambassador from a small, previously unheard - of tribe. They come to Republic City to establish relations, but face many challenges due to cultural differences and political intrigue. Or perhaps your OC has a prophecy about the future of the Avatar world and has to convince everyone, including a skeptical Korra, that it's real.
One idea could be that Ichigo, through some sort of interdimensional rift, ends up in the Avatar world of Legend of Korra. He could initially be seen as a threat due to his otherworldly powers. But as the story progresses, he teams up with Korra to fight a common enemy that is trying to take over both their worlds. His Soul Reaper powers could be used in unique ways, like using his Getsuga Tenshou to blast away dark spirits that are plaguing the Avatar world.
One idea could be a crossover where Naruto, with the power of the Kyuubi, somehow ends up in the world of Legend of Korra. He could team up with Korra to face a new threat that combines the dark jutsu from Naruto's world and the bending abilities in Korra's world.
One possible plot could be that the girl has some sort of unique ability that Naga senses. Naga licking her could be a way to either gain or transfer some of that power. The story might then revolve around how the girl and Naga interact further because of this connection, and how it affects the overall world of 'The Legend of Korra'. For example, they might have to face some common enemies or challenges together because of the special bond formed by Naga's licking.