It feels when many reminisce upon old memories playing the Pokémon Trading Card Game, characters such as Charizard, Scyther, and Mewtwo immediately come to mind. Given the success of the franchise even very early on into its life span, a card game based on the series appeared to be a fun notion. The card game is still thriving through collectors and a competitive scene that sees no signs of dying anytime soon. This thought process makes one wonder, what Pokémon cards were the most competitively viable in tournaments? Was their ever a definitive most "powerful" card?
Before discussing exactly why particular Pokémon cards were so strong, it's important to describe how the card game is balanced. Every year or so, sets from the previous year are "rotated out of the format". What this means, is that after a certain amount of time, older cards aren't available to be used in newer tournaments. This keeps players on their toes, encourages them to test different decks, and also gives players motivation to invest in new booster packs. This means that at any given time, certain cards are simply not viable. Despite this, certain cards in particular formats have been dominant.
In terms of raw damage output, there is a Shadow Lugia card that does 1000 damage while having a colossal 300 hit points. If a card like this were playable in the actual trading card game, it would be overpowered. However, this Pokémon card was used as a promo item for Pokémon XD Gale Of Darkness, and due to this, it came in the form of a giant card. Due to this, the card could not be physically played in a deck. However, it is technically the most powerful Pokemon card ever created. 1000 damage with an HP of 300 is not only a huge challenge to take down, but it will always take down your Pokémon in one fell swoop too.
The Strongest Playable Pokemon TCG Card
While the Shadow Lugia card is certainly the most powerful Pokémon card in existence, an inability to be used puts it in a strange position. Among playable cards, what were some of the most dominant? Early on in the Pokémon meta, cards like Scyther and Hitmonchan were very powerful due to high damage output with small energy costs. This made them powerful yet low committal options. Another hugely powerful Pokémon card was Luxray G Lvl X, a card that could move a benched card directly to the active spot. Luxray dominated high-level play for many years, as he was often paired with Garchomp for an effective deck archetype.
Recently some of the more powerful cards have been trainer and supporter cards. Pokemon Catcher was a trainer card with the same effect as Luxray G Lvl X's ability. Needless to say, this card was very heavily utilized for how powerful it was. At one point, the card was nerfed, requiring a coin flip to utilize its oppressive ability. Another interesting card is the supporter card Lysandre's Trump Card, which forces both players to shuffle all of their discarded cards back into their deck, effectively preventing a deck-out from ever happening. The card was later banned because it removed a win condition (running out of cards in your deck) from even being possible.
After taking a look at Pokemon's long-standing meta, it becomes difficult to say which card was the most powerful. In terms of raw power, Shadow Lugia is the strongest. However, it's an inability to be played holds it back from such a title. For now, it seems the definitive "strongest" playable Pokémon card has yet to come.