She's not really a one-hit Wonder Woman villain (as I don't this she ever appeared in the Wonder Woman title in the main continuity), but I have a love for the Earth 3 doppelgänger, Superwoman.
She always seems to be a more of a supporting character to Ultraman or Owlman in any Crime Syndicate story, but I think she has so much potential. I'd really like to (and have in my own thing I'm working on) dig into her background on the world of Earth 3 and develop some great motivation for her animosity towards Diana, Hippolyta, and the Amazons.
I'm definitely jettisoning the Morrisonian aspects of tying her into the Superman mythos with the pseudonym "Lois Lane" and making her origins wonderfully evil and Amazon-ily malevolent.
I hope whenever Doomsday Clock concludes or however the Multiverse reboots itself, we get a new Earth 3, because I think she's "mostly" dead post-Darkseid War.