Looking at old history books and, in particular old world history books on paintings, you’ll see pictures that are not shown these days. Not that the paintings are any less prolific than a Van Gogh or Leonardo, but because editors, educators and governmental schooling are opinionated as much as the writers.
I try to purchase as many college textbooks, art historical books and books on art in general as I can afford because every book will teach you something different, even if the subject is the same. For example, all of them fulfill the requirements of ancient cave paintings, Egyptian, Greek and Roman empires, Leonardo da Vinci, Rembrandt, as well as Cezanne, Monet and Picasso (if it were written in the 19th century). For the younger generations, it is similar to doing searches in a variety of search engines, rather than just getting your information from Google and God forbid, Wikipedia.
A Picture History of Painting From Cave Painting to Modern Times by H. W. Janson and Dora Jane Janson is mostly black and white, with a few color plates about art. Now, most of the book is pictures rather than texts, but that is the beauty of it, many paintings—paintings that you haven’t seen before in modern textbooks.
This book is public domain. You can get a PDF version of it here (it will open up a new tab or window): Picture History of Painting.