Here are some ways to consider what makes a card powerful:
* Competitive Play: In competitive Pokemon trading card game (TCG) play, power is often measured by a card's ability to win games. Here, a card like Pikachu & Zekrom-GX from the Sun & Moon era has a powerful attack and a useful ability, making it highly effective in competitive formats.
* Rarity: Some cards are considered powerful because they are incredibly rare and valuable. This is often the case with promotional cards or limited edition sets. For example, the "Gold Star" cards from the Diamond & Pearl series are highly sought after.
* Nostalgia and Sentimental Value: For some collectors, the most powerful cards are those that hold special significance, such as a childhood favorite or a card from a memorable event.
Therefore, the "most powerful" card is subjective and depends on your individual definition of power.
Here are some other factors to consider when choosing a "powerful" card:
* Attack Power: How much damage can the card inflict?
* Ability: Does the card have a special ability that can benefit your strategy?
* Type: Does the card have a type advantage over common opponents?
* Energy Cost: How many energy cards are needed to use the card's abilities?
* Rarity: How rare is the card?
Ultimately, the most powerful card for you is the one that best suits your playing style and goals.