Now more than ever (seeing as the Supernovas are entering alliances), Jewelry Bonney. If she in fact has escaped the WG, which is more than likely seeing as her timeskip depiction shows her portraying a more hidden demeanor, she likely has no crew and is wondering about the NW either searching for a new crew or simply trying to stay out of the center of attention. That being said, she has numerous vendettas unsolved as of yet; BB, Akainu/WG, even the SHs. She appears to have a tragic backstory, a must for the crew, and also a rather comical and unique personality. Plus she's a girl for an otherwise masculine-dominated crew (not a very strong argument I know, but a thought nonetheless). Joining the SH's would plausibly resolve/fulfill each of these points.