The Avenger
Bill Barnes
Frank Chandler, aka Chandu, the Magician
Jimmy Christopher, Operator #5
G-8
Flash Gordon
Dr. Henry "Indiana" Jones, Jr.
Kerry Keen
Rick O'Connell
Doc Savage
The Phantom Detective
Secret Agent X
The Shadow
The Spider
The Whisperer
Hans Zarkov

Pulp Heroines

Link: Pulp and Adventure Heroes of the Pre-War Era Web-Site (by Jess Nevins)