The Strength Expansion Pack Sky Legend is a subset containing 69 cards that was released on April 26, 2019 in Japan. The subset introduces Z-Crystals to the TCG as Pokémon Tool cards which give a GX attack to a Pokémon provided it has a specific attack. There is a particular focus on the Grass, Water, and Colorless types, as well as Legendary, Mythical, and Ultra Beast Pokémon. The set debuts the first Tag Team card that combines three Pokémon, in this case, the Legendary birds: Articuno, Zapdos and Moltres.