I'm not sure whether to class Randall Garrett's alternate history "Lord Darcy" stories as Steampunk, or precursors of Steampunk. In the alternate universe, magic works, which has held back the development of technology to the point that by the 1950s, the world's technology base was just getting to where it was in Victorian times, in our timeline. Both Garrett's original stories, and the continuations written by Michael Kurland are good reads, though.