The Gotham City Sirens were a team forged by Paul Dini in the Batman comics after the apparent death of Bruce Wayne. It consisted of Catwoman, Poison Ivy, and Harley Quinn. If rumors are to be believed, the TV show Gotham is trying to make their own version of the Sirens. But this one features Barbara Kean and Tigress. Though not named as such in the show yet, the actresses behind the characters are saying they’re called that. And, it looks like Season 04 could see the rise of them. As Tigress herself Jessica Lucas has said the following:
“Oh, I don’t want to spoil anything, but I think that is the plan,” Lucas said in an interview with Heroic Hollywood. “I love that they started it out in an unexpected way with Barbara and Tabitha because neither one of those characters are part of the [Gotham City] Sirens in the comic books. But I think there is room for growth, there is room for new members and I think it would be great to have some sort of girl gang going on next season. So I hope so, but I’m not sure yet!”
It would be an interesting twist, especially since it’s stated that the shows version of Catwoman will be learning from Tigress this season. So you never know.