As the title suggests, I was wondering if anyone knows of any common themes or motifs that are usually found in dieselpunk related stories.
I've been doing research on my own & I know that the most common themes include dystopian societies, emphasis on the World Wars, & a focus on fads of the era such as Jazz. However, I was hoping if to see if there any other themes that I may have missed or may not be able to find on other sites.
Kind of a hard topic; the little bit of DP lit that I've read is all over the place (and some of it totally disregards what you already have on your list). A few things that do come to mind (and again, I've also seen plenty that disregards them) is a positive view of science to make things better (or at least more interesting) and fascination with flight (dog fights, biplanes, zeppelins, etc.).
Dystopian societies, alternate history, weird/mad and/or anachronistic science/technology, art deco and/or brutalist architecture, jazz or electroswing.
I found this in the Dieselpunk Encyclopedia and thought it might be an interesting take on your question. I don't think it's quite exactly what you mean, but hopefully it give some insight:
"Common Themes Found in Dieselpunk Fiction
"A feature that was first identified by the online magazine The Flying Fortress is that dieselpunk can be divided into two primary themes or styles: Ottensian and Piecraftian. The dividing line between the two themes is commonly acknowledged as the start of World War II.
"One theme, named “Piecraftian” after its proponent author “Piecraft”, focuses on the aesthetics of the world wars and speculates on how human culture could theoretically cease to evolve due to constant, widespread warfare. According to Ottens and Piecraft this theme continues the aesthetics of the diesel era into later periods of history by describing a world where survival (largely based on a reliance on diesel power) is placed above aesthetical evolution (as seen in such dystopian movies as Mad Max).
"A second theme, named “Ottensian” after its proponent author Nick Ottens, focuses on a setting where the decadent aesthetics and utopian philosophies of the American “Roaring Twenties” continued to evolve unhindered by war or economic collapse. Ottensian dieselpunk fiction is primarily concerned with a positive vision of technology, where the utopian ideals predicted by the World’s Fairs of the times came to light. As a result Ottensian dieselpunk incorporates “an enthusiasm for the predictions about the future,” and often shares elements with retro-futurism."