Biomedical Ephemera, or, a Frog for your Boils is "A blog for all biological and medical ephemera, from the age of Abraham through the era of medical quackery and cure-all nostrums. Sometimes featuring illustrations of diseases and conditions of the times, sometimes fascinating ephemeral medical equipment, and sometimes clippings and information about the theories themselves." The archive page is also a useful starting point. via Things Magazine.
Art Images for College Teaching is a searchable, browsable collection of 2,027, well, art images for college teaching, and appears to be mainly the personal collection of Art Historian Allan Kohl (previously on MeFi), and thus represents his interests and specialities, not to mention the variable quality of his photographic skills. Rather strong in Ancient and Medieval, especially architecture, but tapers off as you become more distant from Europe or closer to the 20th century. Nice sets include the Lion Hunt from Ashurbanipal, Iraq; the exterior sculpture of Chartres; and grave stele.
Agence Eureka is a French language image-blog with hundreds or even thousands of scanned illustrations, mostly from mid-20th century French schoolbooks, educational material, magazines, and ephemera. The current front page is slightly NSFW. Some of the categories include anatomy 1 & 2 (mildly NSFW); chocolate wrappers/trading cards; bricolage; decoupage (cut-outs); math education; playing cards; books and magazines; cars; cinema; orientalisme; sport; mild pin-ups; and many others (scroll all the way down the right to see the tags). [more inside]