This Audrey Hepburn photo contains
boater, leghorn, panama, panama hat, sailor, skimmer, straw hat, fedora, felt hat, homburg, stetson, trilby, porkpie, and porkpie hat.
There might also be
beaver, castor, dress hat, high hat, opera hat, silk hat, stovepipe, top hat, topper, beaver, and campaign hat.