Joe R. Lansdale & the Weird Western
I can't remember which was the first story I read by Joe R. Lansdale. It might have The Drive-In, a strange science fiction tale where aliens (or something similar) take over a Texas drive-in, transport it and the attendees to an alien world and torment them for no apparent purpose. (There were two sequels, all available in the omnibus edition The Complete Drive-In.)
That was atypical, though. Most of his fiction is set in a close approximation of the real world. He writes crime stories, horror stories and westerns, sometimes all three at the same time.
Weird westerns, that is: stories that use the tropes and characters of the western, but take them in unusual directions. He did this both as author and editor.
As editor, he compiled three (now out-of-print) western anthologies -- two of which were published under Doubleday's traditional Double D Western imprint: The Best of the West: An Anthology of Western Writing from the Western Writers of America, The New Frontier: The Best of Today's Western Fiction and Razored Saddles: The Cowpunk Anthology (a back construction from cyberpunk and steampunk, incorporating cowpoke, that probably no one else ever used).
In the story, Elvis Presley is alive -- he traded places, a la The Prince and the Pauper, with an Elvis impersonator, who then died -- but is now stuck in a nursing home with a broken hip. His best friend is a black man who claims he is JFK, dyed black. The two discover that an Egyptian mummy in cowboy garb -- don't ask -- is sucking the souls out of residents of the nursing home, and team up to stop him. It ends in a western-style showdown. It's absurd, comical and yet strangely moving and tragic. Bruce Campbell and Ossie Davis star in the film version, which is a very faithful adaptation of the story.
Lansdale's most popular work is the Hap Collins and Leonard Pine series (eight novels so far and a few shorter works, of which my favorite is the second, Mucho Mojo), set in modern Texas and featuring Hap, the narrator, a ne'er-do-well white man, and Leonard, his gay, black friend. The stories are crime fiction akin to Elmore Leonard (does that make them modern-day westerns?), but I thought I'd mention them.