I want one of my characters to be a Native American Cryomancer/Aeromancer named Winterhawk, and he's got a tattoo of wings on his back done by his village's witch doctor that can grow out into actual white-feathered wings. As a Battlemancer, he will likely take flight and then fling ice spears from the sky XD.

Two other character ideas: Someone with a powerset similar to Luck from Black Clover, combining Electromancy and Cerebromancy; and a guy who used Ecomancy and Pryomancy to create green flames that heal people. 

One thing I want to remind everyone - because there are so many potential uses for each combination, please don't worry about having too many people with similar powers. If someone else has already shown interest in two Arts you wanted to use, it's still fine for you to use them, just make your application of it unique.