I hoped to find a pattern for the crown-like thing on the front of Vaati's hat, but nobody had uploaded one. So here's the one I made, for a costume I'm making for my sister. Hopefully it can be of some use to someone. I'm making this part out of craft foam so it's easy and lightweight.
This file is formatted at 10 x 7.5 in (25.4 x 19.05 cm) to fit on a standard sheet of letter paper in landscape format. Resolution is 150. In the completed pattern, the largest piece (part "A") is 11.75 inches (28.575 cm) wide.
Free for use, alternation, and distribution. I'd appreciate a comment if you use it, though!