This Michael Jackson photo contains
academic gown, academic robe, judge's robe, fedora, felt hat, homburg, stetson, trilby, dress hat, high hat, opera hat, silk hat, stovepipe, top hat, topper, and beaver.
There might also be
boater, leghorn, panama, panama hat, sailor, skimmer, straw hat, porkpie, porkpie hat, and snap brim hat.