This The Walking Dead photo contains
fedora, felt hat, homburg, stetson, trilby, boater, leghorn, panama, panama hat, sailor, skimmer, straw hat, pith hat, pith helmet, sun helmet, topee, and topi.
There might also be
dress hat, high hat, opera hat, silk hat, stovepipe, top hat, topper, beaver, campaign hat, and business suit.