Every type of sub-bending in Avatar: The Last Airbender
Air:
1. Flying
While all airbenders have the ability to fly with a glider, there is an extremely rare ability that lets the bender fly unassisted. As far as we know there are only two people who have done this, starting with Guru Laghima. Laghima was a airbender and philosopher who lived in the Northern Air temple thousands of years prior to the time of Avatar Aang. The Air nomads studied Laghima's writing for generations. He is regarded as one of the wisest people to ever exist in the Avatar world.
At some point in his life, Laghima achieved weightlessness, and in turn the ability to fly without the assistance of a glider. This feat requires achieving a state of enlightenment that involves letting go of all worldly tethers. Instead of flying like superman, the series' creators wanted the flight of an airbender to resemble a kite moving through the sky.
In The Legend of Korra, the Red Lotus leader Zaheer is a student of Laghima's writing and regularly quotes passages from his poetry. Zaheer obtained the ability to airbend after harmonic convergence and set himself on the path to learning Laghima's legendary flying ability. The last earthly tether holding Zaheer back was his love for the combustionbender P'Li. It was only after her death that Zaheer was able to achieve weightlessness and fly like Laghima.
2. Spiritual projection
This airbending skill allows the bender to project their spirit out of their body and travel to other locations in a ghost-like form. Aang's granddaughter Jinora is the only person we see use this ability onscreen. We know it requires a strong spiritual sense. In addition to being able to move freely through walls, water and other obstacles, the projector can hone in on someone they have a strong connection with and appear to them.