Knit in some thrifted wool. I found some multicolored wool matching the main color- almost too close, since some of it matches exactly, making colorwork a bit tricky! The multicolored yarn worked best in the corrugated ribbing, which really shows off the colors without losing the pattern.
I tried to keep the body simple to show off the colors without any complicated colorwork- just a bit of checkerboard which got a bit lost. As usual, I did a quick decrease over several rounds to finish off the hat. next time I would work the multicolor in garter ridges interspersed through the body of the hat to make it pop a bit more.