Cowboy Hat

The Clothier is the only seller, and he keeps this stock hidden twice over. Your world has to be in Hardmode, and the moon has to be at first quarter when you open his shop. Phases advance one step per dawn on an eight night loop, so a missed evening costs you most of a week.

Check him at dusk instead of during the day. When the phase lines up the hat, jacket and pants all appear together, so clear the gold beforehand and take everything in one visit.

Everything is worn in the social slots, which means the brim and the duster ride over your armor without touching how you fight. The hat carries the look on its own if you would rather keep your other vanity slots for something else.