This Mary Morstan Watson fan art contains
boater, leghorn, panama, panama hat, sailor, skimmer, straw hat, campaign hat, fedora, felt hat, homburg, stetson, and trilby.
There might also be
sign, poster, text, chalkboard, dress hat, high hat, opera hat, silk hat, stovepipe, top hat, topper, beaver, pith hat, pith helmet, sun helmet, topee, and topi.