Yes, in some of the visual novels, there are hints at new or modified bending techniques. For example, in certain story arcs, characters might combine different types of bending in unique ways, like using water bending to enhance earth bending in a specific situation. But it's not like there are completely new types of bending out of the blue.
Avatar: The Last Airbender is indeed an original story. It has its own distinct style and narrative that sets it apart. The combination of elements like bending powers, diverse characters, and complex story arcs make it a one-of-a-kind creation.
Definitely not real. It's a fantasy world crafted with unique characters and magical elements that exist only in the realm of imagination and storytelling.