This Flickr album has a series of covers of British pulp science fiction magazines. There’s lots here for inspiration.
Pulp
Retro Tank Paper Model
Here’s a beautiful free paper model of a retro tank. It looks like a lot like some of the tin tanks that my grandparents had stored in their attic — they belonged to my uncles. This would be useful for a variety of early 20th century pulp games.
Spielberg’s Inspirations For Raiders
Shot-by-shot comparison of “Raiders of the Lost Ark” vs. scenes from 30 different adventure films made between 1919-1973.
Indiana Jones: The Animated Series
No it is not really a series, but merely a fan-made “trailer” for a non-existent cartoon show.
Nonetheless, it is full of pulp goodness.
Science Fiction Pulp Magazines and Comics
Comic Books Plus has a collection of free pulp era Science Fiction magazines and comics.