When a Harley-centric follow-up to Suicide Squad was first being dreamt up, ths idea of a Birds of Prey films was percolating concurrently with a Gotham City Sirens movie – the latter another team comic book, but with Harley Quinn, Poison Ivy and Catwoman. While that’s not what we ended up getting, it’s easy to see the DNA of that book in the upcoming film.
Spinning out of the aftermath of “Batman R.I.P.,” Gotham City Sirens would do a lot to establish the relationship between three of the most iconic women in Gotham. They never quite trust each other but the groundwork is laid for their eventual characterizations through the present day. “Ends” closes out the series and writer Peter Calloway gives them a way forward. Despite the struggles and their sometimes very tenuous relationship, Ivy, Selina and Harley do right by each other because they realize that they have formed a significant bond.
This one makes the list with the caveat that it reads a lot better if you’ve read the 22 issues that precede this arc – but it’s still a solid story for fans looking to understand the ecosystem of Gotham and how characters like Harley Quinn fit into it.