Dr. Cyber, like Giganta, is another Wonder Woman villainess that persists in the consciousness of fans despite creators doing their level best to ignore her. In Giganta's case, she had stories dating back to World War II, and fans from the Superfriends cartoon, but didn't return with any regularity to the Post-Crisis comics until Phil Jimenez restored her relatively recently. Cyber didn't arrive until 1968, but she became the primary foe of Diana Prince during the depowered/white jumpsuit years.
Cyber was originally very much of the James Bond/Avengers threat mode, the head of an international, hi-tech criminal organization that caused earthquakes and such. When Cyber was disfigured during the collapse of one of her schemes, she erroneously blamed Prince, and set about evening things up. Whether through brain transplants or outright removing Wonder Woman's face, Cyber not only wanted her beauty restored, but her foe's destroyed, making her menace both very personal, horrifying in nature, subtextually potent.
Once Wonder Woman's powers were restored, Doctor Cyber also received an upgrade, wearing advanced armor that made her resemble a female Dr. Doom. Again, Cyber pits technology and the visible absence of humanity against the paganistic super-powers of the quite fleshy Amazing Amazon, serving as a perfect conceptual counterpoint for the heroine. Unfortunately, Dr. Cyber was cast aside after the Crisis, disappearing for a decade & a half, and returned as a b-villain in the Power Company series. Only recently has Dr. Cyber turned up in Wonder Woman's circles again, but with negligible prominence, so her supports continue to wait...
5) Wonder Woman #321 (November, 1984)
Cool cover, but Cyber is in a position of weakness.
4) Wonder Woman #188 (June, 1970)
I initially had this in the second spot, but Cyber is obscured to androgyny, there's no background, the colors are boring, Diana doesn't sell the bondage, and you have to read a bunch of dialogue to know what's going on.
3) Wonder Woman #320 (October, 1984)
There's a whole lot more Steve Trevor than is necessary, but this is the only cover of Dr. Cyber proactive in her armor.
2) Wonder Woman #221 (January, 1976)
Hawkman bleeds a lot of the tension, as does Cyber's Mother Bates dress, but this is terribly literal in a way #188 failed to be. Grotesque villainess wielding a scalpel against a bound Wonder Woman's face while forcing her to watched is seriously messed up, which is why it works.
1) Wonder Woman #200 (June, 1972)
This is kind of a terrible Wonder Woman cover, since the flowing gown represents neither the Amazing Amazon nor globe-trotting butt kicker Diana Prince. However, Dr. Cyber is all kinds of creepy, marrying her pre-and-post armored vibes. You know she's planning something gut-wrenching and awful, "The Beauty Hater" makes it clear what, and the Gothic atmosphere makes you afraid she just might do the deed!
Check out more spotlight countdowns of great art from the past 75 years of DC Comics Covers at DC75: Top Character Covers of the Dodranscentennial