I nominated the Ink Beast Parade, which is a set of images created by Augustus Jansson as advertisements for Queen City printing ink between 1905-1908.
I used labels from the images themselves (i.e. "The only heliotrope cow in the world") to label them, or if there wasn't a label, a combo of a colour used and the animal (golden yellow bear), but if you need more specifics, please let me know.
Evidence: The Ink Beast Parade
An article with large versions of the advertisements
Public Domain Review piece with additional images
I used labels from the images themselves (i.e. "The only heliotrope cow in the world") to label them, or if there wasn't a label, a combo of a colour used and the animal (golden yellow bear), but if you need more specifics, please let me know.