Two alternate covers: Witch World (10th Ace edition, 1984; see the Witch World Section) and Victory on Janus (2nd Ace edition, 1973; see The Collection).
Others are Dark Piper, Dragon Magic, Forerunner, Forerunner Foray, The Mark of the Cat, Night of Masks, Sargasso of Space, Voorloper, Wheel of Stars, and Wraiths of Time (all in The Collection).