Of the approximately 850 post office muralists, the overwhelming majority are artists I had never heard of. Many have little to no work available for viewing via the web. A few are quite famous. And some should be more famous than they are. Bearing in mind that, to an extent, my knowledge (or memory) is limited to art history books and classes.
Mitchell Siporin is an artist I really feel I should have heard of before now. He is (or was) my favorite type of social realist (a touch of the surreal is in many of his works). You can see examples of his work at the Smithsonian American Art Museum’s website, Haus der Kunst, and the Whitney.
Mr. Siporin painted two post office murals: Fusion of Agriculture and Industry (Decatur, Illinois) and Cycle of History of the Region (St. Louis, Missouri).