There are the tame subject matters, often selected by middle-class homes and classrooms: pictures of dogs, kittys, horses, natural scenery.
And for guys (and gals leaning in that direction), there's the swimsuit calendars; the most widely sold being the Sports Illustrated Swimsuit Calendar. And, with smaller production values and usually with smaller circulations, there's the university- or sports team-specific calendars:
Sometimes these stir up controversy:
But, mostly, controversy is free publicity that drives up sales.
I'm sure there will be others. I just wanted to make the point.
And then there are the art calendars; especially favoring the Impressionists and the Preraphaelites. I'm sure there are a few that include German Expressionism; and (who knows) maybe even Soviet Realism. And unusual interests:
I wonder if someone will come up with really grotesque ones. To my knowledge, a calendar dedicated to controversial art works has not been marketed. Howver, Manet's Olympia and Goya's Disasters of War should surely be included. Maybe they might even make space for Robert Mapplethorpe or Andres Serrano; even though (in my opinion) their fame rests on a succès de scandale and not on any enduring value.
RyanAir Cabin Crew made a calendar, with the proceeds going to charity:
How about a calendar honoring a tavern:
Or Jersey Guys:
But wouldn't the last frontier be a Members of Congress Swimsuit Calendar? Can you imagine Harry Reid or Mitch McConnell or David Vitter decked out in a speedo? Or how about Nancy Pelosi in a bikini? Are you ready for some lunch now?