A female-centric comic book movie is currently in development and it would be led by Margot Robbie as Harley Quinn.
Suicide Squad is building the kind of buzz that Batman V Superman would've given its right nut for; it looks a bit off-the-wall and the trailers have been pretty great so far. So, essentially, there's a bit of a bang of Deadpool off of it.
Central in the trailers has been Robbie's Quinn, who would feature in the spin-off as would Batgirl. In the comics, Harley Quinn routinely breaks the fourth wall in a similar way to Deadpool, which was obviously an extra push for Warner Bros. given how well that property performed for Fox.
Robbie is fast becoming a huge name and has made multiple films for Warner - including this summer's Tarzan and Focus. She'd also serve as a producer on the DC movie.
Be interesting to see if they go with an 'R' rating for this one. Harley Quinn would shine in that kind of boundary pushing flick.