Who's This? The minor hero who, despite being an 80s music video nightmare, is the most gorgeous pic in all of Who's Who vol.XVII (art by Jerome K. Moore, on page 16).
How you could have heard of her: Onyx wouldn't make another appearance until 2001, when she was part of Wonder Woman's team fighting Circe (Wonder Woman vol.2 #174-175), a glorified cameo, no more. From there, and with a completely OTHER dated look, she became a member of the Batman Family shortly before and during the War Games and Family Reunion storylines of the mid-2000s. Her last post-Crisis appearance was another cameo, in 2008's Birds of Prey #114. A new Onyx has shown up in the New52's Green Arrow book, looking deathly pale leading some to call DC Comics out (again) for white-washing a character. Jeff Lemire says she's not Caucasian, but it's unclear from the art what her ethnicity might be.
Example story: Detective Comics #566-567 by Joey Cavalieri with Jerome Moore and Dell Barras (566) and Stan Woch and Dave Hunt (567)
Well, aside from a cool look and a REALLY cool Who's Who entry (and a lot of characters have returned just based on that), if Onyx's portrayal was like this all the way through her Green Arrow appearances, I can't really blame anyone for not picking up those story threads. She's kind of flighty, marginally boy-crazy, and once Green Arrow shows up, takes a back seat to the white male hero. It's really too bad and falls far short of the character's potential.
Who else? I was almost tempted to say I was done with volume XVII, but I think there may be one more entry I could do...