Project korra is a great plugin but quite a few of its features need different plugins to work such as spirit bending which you cant use without the add-on. There are also quite a few bendings that need a different add-on to work such as sand bending.
A link to spirit bending add-on.
https://projectkorra.com/forum/resources/spirits.323/
A link to another insanely useful add-on which lets you select abilities in a menu instead of typing every single ability.
https://projectkorra.com/forum/resources/bendinggui.141/
Lastly, here is the link to a list of abilities that allow currently unusable bending such as sand bending and plant bending and expand upon current abilities.
https://projectkorra.com/forum/resources/categories/custom-abilities.3/