Here's more from this 1943 book I have.
Don Herold, Life 1928
Ralph Barton, Liberty 1929
J. Norman Lynd, Vignettes of Life 1930
John Groth, Pretty Pictures 1932
Miguel Covarrubias, Vanity Fair 1932
Otto Soglow, Wasn't the Depression Terrible? 1932
William Steig, Vanity Fair 1934
Marge Henderson Buell, Saturday Evening Post 1934
Alain Dunn, Collier's 1937. I believe this is a different person than the “Alan Dunn” in The New Yorker. Those cartoons were all done in charcoal and wash.
C. W. Anderson, Ballyhoo 1937
Syd Hoff,Collier's 1937
Charles Addams, Collier's 1937
Marge Henderson Buell, Saturday Evening Post 1938
Ed Nofziger, Saturday Evening Post 1939
A. Ross, Collier's 1939