The Pokémon Trading Card Game is receiving its first triple tag team, allowing for the game's original three Legendary birds to fight alongside each other in the latest Hidden Fates expansion for the game.
The Pokémon Trading Card Game added a new type of card in the Team Up expansion called the Tag Team Pokémon-GX cards. These cards involved two Pokémon working together in a single card, which meant that they had strong moves and higher HP than regular cards, with the caveat that their defeat would result in the opposing player winning three Prize cards instead of one. The fact that a Pokémon Trading Card Game match only uses six Prize cards means that it's risky to use two Tag Team Pokémon-GX cards. The GX in the name refers to a mechanic shared by all Tag Team Pokémon-GX cards, as they all have access to an extremely powerful GX move, but only one GX move can be used throughout the entire battle.
The Hidden Fates expansion for the Pokémon Trading Card Game added the first Tag Team card that uses three Pokémon instead of two. The first triple tag team involves Articuno, Moltres, and Zapdos, who debuted as the three Legendary birds of the Kanto region in Pokémon Red & Blue. The Legendary birds have three hundred HP and access to the powerful Trinity Burn attack, as well as the one-shot Sky Legends GX move, which can deal damage to three of the opponent's benched Pokémon. The fact that there are three Pokémon appearing on the card doesn't affect the number of Prize cards that are given away upon their defeat, as a triple tag team still only rewards the opponent with three Prize Cards.
The Tag Team card mechanic debuted in the Team Up set, but it was absent from the following Detective Pikachu mini set, which was meant to promote the release of Pokémon: Detective Pikachu. The Tag Team cards returned in the Pokémon Sun & Moon - Unbroken Bonds set and have been featured in every set since. There will also be more triple tag teams available in future sets, as the upcoming Cosmic Eclipse set is due to feature cards starring Togepi, Cleffa, and Igglybuff, as well as Arceus, Dialga, and Palkia.
It's unknown if the Tag Team card mechanic will return when the Pokémon Trading Card Game reaches the Pokémon Sword & Shield era, as the game will need to introduce cards that use the Dynamax and Gigantamax mechanics from the video games, which is likely tied to the new "V" card type that was recently revealed. The recent information revealed about the online modes in Pokémon Sword & Shield has confirmed that Double Battles will still be part of the competitive battling scene, so there is no reason why the Tag Team mechanic shouldn't remain in the Pokémon Trading Card Game in the future.
Source: Nintendo