Use one color-neutral like burgundy or navy with a primary base of a basic neutral like taupe. Then the mint is a fresh pop.
This is a similar idea using basic neutrals as the base, mint as the primary color, and another bright color as an accent.
Copper is the metallic for fall, and some minty shades work perfectly as aged copper.
You could go 80s-tastic by pairing mint with bold bubblegum pink. Just leave the acid wash and scrunchies in the past.
Of course, you can always try it with a traditional fall palette.