This IU wallpaper contains
fedora, felt hat, homburg, stetson, trilby, snap brim hat, boater, leghorn, panama, panama hat, sailor, skimmer, and straw hat.
There might also be
porkpie, porkpie hat, beaver, castor, dress hat, high hat, opera hat, silk hat, stovepipe, top hat, topper, and beaver.