The Gotham City Sirens (sometimes abbreviated as Gotham Sirens) are a team of 3 female villains who Batman has fought before, Catwoman, Harley Quinn and Poison Ivy. A series about their adventures was produced.
Batman: The Animated Series
In "Harley and Ivy" the girls shows their feet while wearing more revealing attire while in Ivy's hideout. Initially Harley Quinn is barefoot prior to Poison Ivy entering and their being barefoot simultaneously. Harley is the first to notice Batman joining them.
A sole foot is shown adjacent to a vine attacking Batman. It isn't entirely clear whose it is since they are standing side by side barefoot, but it is probably Poison Ivy's since she is the one who controls the plant.