I was joking a bit with my post about "irrelevent" pop girls lol.
Christina Aguilera is one of the biggest pop girls in my life time lol
Dev had a few other hits (like Bass Down Low, Backseat and In the Dark)
Janelle Monae is currently #31 on urban
Lauren Bennett as going to be in the new line-up for the Pussycat Dolls, but they cancelled that I think, and she was in another girl group before iirc
Nayer had a hit in some European countries I think
Not sure if Kimbra has had any other success though