Power Girl usually wears a Leotard of Power that shows off her powerful legs along with her signature cleavage window.
Poison Ivy: Boy, does she know how to use 'em. Her leggy figure is usually emphasized whether she's wearing leotards (with or without green tights), her black-and-green skintight outfit, nothing but plants, or nothing at all.
Raven from Teen Titans was this while being rather slim, especially compared to Wonder Girl and Starfire. Her costume includes a long skirt that is slit to the waist to accentuate her legs.
Robin back in the 1960s, '70s and '90s were male examples, with Dick Grayson and Jason Todd wearing the iconic tiny little green shorts to show off their muscular legs while crime fighting. When Tim Drake took up the role, he switched out the shorts for green trousers. The only girl to show off her bare gams in the Robin outfit was Carrie Kelly in The Dark Knight Returns
Supergirl's legs are given focus with most of her costumes incorporating a short skirt. Kara's redesign in New 52 went further with this by ditching the skirt to show even more of her legs.
Tim Drake: Robin: Darcy is pretty much always in very short shorts, which show off the large floral tattoo she's got up her left leg. She even wears shorts as Sparrow, despite her tattoo making it unlikely she'd be able to maintain her secret identity if she ran into anyone she's ever met before.
Wonder Woman, a literal Amazonian Beauty, tends to wear a strapless leotard, bustier-hotpants combo, or a form-fitting body suit that highlights her muscular legs.