I found out about Cresselia just now and that got me wondering, are there any others?
Male Latios Heatran Tornadus Thundurus Landorus Kubfu Urshifu Solgaleo (canonically, genderless in-game) Zamazenta (canonically, genderless in-game) Calyrex (canonically, genderless in-game)
Female Latias Cresselia Heatran Lunala (canonically, genderless in-game) Zacian (canonically, genderless in-game) Kubfu Urshifu Enamorus
Legendary Pokemon on Bulbapedia
Hope I helped!