Striped tights are available in both horizontal and vertical striping. While horizontal stripes are easier to find I personally think they are more Wicked Witch than Steampunk. A pair of brown/white stripe, and a pair of black/white stripe tights are an excellent addition to any Steam wardrobe.
While not strictly a steam inspired piece a variety of fishnets will accent a variety of looks. These go especially well with shorter bustle skirts that show a more leg.