Anything Streamlined from buildings to locomotives and autos, ashtrays to telephones.
Streamline Moderne is a late architectural and industrial design form that grew out of Art Deco. Deco usually emphasizes verticality with lines soaring skyward. Streamline Moderne emphasizes lines that stream back horizontally, often with curved surfaces that look like they are being pulled back by the wind.
I don't have a large collection of these photos. But I was surprised to see that Streamline Moderne seemed to be neglected. I'll strart looking around and find some local examples to post, and I'm sure I have some in my collections.