The first pop girl that comes to mind is Cheryl. I usually end up only using a single here or there because most of her albums are filler to me
Nicole Scherzinger's another one like that for me, except I liked a good portion of her most recent album.
Others mentioned already that I kinda agree with are Demi, Christina (on certain albums), and Jennifer (I always end up loving her singles, but her albums, bar Love?, are usually very hit or miss for me).
