×Close Collector's Cosmetics: The ultimate TF2 collectable. Collector's Chemistry Cets were rare drops, and seemingly any weapon or cosmetic in the drop system could be found as a Chemistry Set output. While Collector's Chemistry Sets for weapons were rare, Collector's Chemistry Sets for cosmetics were insanely rare (many cosmetics simply don't have chemistry sets). To own a Collector's Cosmetic is proof undeniable that you are a true collector!