I have some ideas for waterbending cause the new Avatar movie is coming out soon and also why not.
Lighting distortion/absorption:
Since certain types of water can conduct electricity, a waterbender could carry water that can conduct electricity and use to block the attack. However, the electricity can reach the waterbender in they are to close or have more water touching their body. It is a high skilled ability and only skilled waterbenders can do.
Phantom waterbending:
A waterbender could use the small droplets in the air or just get water and vaporize them into smaller droplets, and then increase the pressure and density to move objects. There are limits though;
- Lesser water = Less effective
- Takes a lot of energy and concertation to do
- Can only be used on certain objects that are at least small. Medium objects are a maybe, large objects are impossible and will require more water.
Humidity Scan: The waterbender turns a blob of water, large enough to cover enough area, and then turn it into vapor. Water molecules can sometimes either bounce off or stick to objects. A waterbender, if focused enough, could feel if certain water molecules are bouncing off objects or just more than usual. ITs more of an ability to scan your surroundings. But I'm not so sure about this one.
Fruitbending & Foodbending: While I'm pretty sure an airbender could do this too since all food contains air, a lot of food also contains water. And a water can pretty much control anything with water in it. They could bend mostly fruits like pears and grapes. I low-key just imagined Aang doing that thing with the marbles, but just a waterbender using grapes.
These are just my ideas, please feel free to names some too for any other element. I would like to see.