That blew me away when I learned that the Klingon Kang voiced Victor Freeze. As Publiusr noted, he made that role his own! In later stories, the production "dialed down" the effects for his voice, but as heard in his debut, that voice would have been perfect for a Cyberman. Not flat out "robotic", but rather, "augmented" with still an element of "humanity" to it. Well, not so much "humanity" as "organic" but bereft of emotional context. That pretty much matches the theme of the Cybermen.