Pulp magazines had awesome illustrated covers, with a very particular style, known as the pulp art. Some artists still come up with amazing pulp illustrations, now filled with pop culture references, which is awesome!
Ástor Alexander, a Californian artist, has illustrated a beautiful set of pulp covers... you can check some of them below.
Pulp covers were printed in color on higher-quality (slick) paper. They were famous for their half-dressed damsels in distress, usually awaiting a rescuing hero. Cover art played a major part in the marketing of pulp magazines. The early pulp magazines could boast covers by some distinguished American artists
Covers were important enough to sales that sometimes they would be designed first; authors would then be shown the cover art and asked to write a story to match. Later pulps began to feature interior illustrations, depicting elements of the stories. The drawings were printed in black ink on the same cream-colored paper used for the text, and had to use specific techniques to avoid blotting on the coarse texture of the cheap pulp. Thus, fine lines and heavy detail were usually not an option. Shading was by crosshatching or pointillism, and even that had to be limited and coarse.
For more of Ástor's work, please visit his portfolio at Behance. I hope you enjoy these! Cheers. ;)