I have at least one box full of pulp science fiction magazines from the 1950's. I haven't listed them yet because I can't find a proper category. The only categories that I could use would be Magazines/Vintage or Magazines/Other, and they'll be buried in either of those.
I am aware of three important subcategories of pulp fiction --- Crime, Science Fiction, and Westerns. There are collectors who buy ONLY pulps, and have no interest whatsoever in paperbacks or hardcovers.
eBid has a massive number of categories for comic books, and in the U.S. these are a similar kind of collectible. They usually have garish covers and (of course) are printed on pulp paper. Some of the rare ones have sold for thousands of dollars, so it's not a trivial thing to ask to have them in a category of their own, separated from the other forms of fiction.
These would solve the immediate problem.
Magazines/Pulp/Westerns
Magazines/Pulp/Science Fiction
Magazines/Pulp/Crime
Magazines/Pulp/Other