Card advantage (often abbreviated CA) is a term used in collectible card game strategy to indicate one player having access to more cards than another player, usually by drawing more cards through in-game effects. The concept was first described early in the evolution of Magic: The Gathering strategy, where many early decks relied on a player drawing more cards than their opponent, and then using this advantage to play more cards and advance their position faster than their opponent. By 2007 it was recognized as one of the most important indicators of who is ahead in a game and has been utilized in the development of strategy for nearly every collectible card game created.

https://en.wikipedia.org/wiki/Card_advantage

Metagaming is any strategy, action or method used in a game which transcends a prescribed ruleset, uses external factors to affect the game, or goes beyond the supposed limits or environment set by the game. Another definition refers to the game universe outside of the game itself. In role-play situations, for example, it would mean to tell somebody some information about another player or something they are doing that the said player's character should not intrinsically know about. In simple terms, it is the use of out-of-game information or resources to affect one's in-game decisions.

In popular trading card games, such as Magic: The Gathering, Pokemon Trading Card Game, or Yu-Gi-Oh! Trading Card Game players compete with decks they have created in advance and the “metagame” consists of the deck types that are currently popular and expected to show up in large numbers in a tournament. The knowledge of metagame trends can give players an edge against other participants, both while they are playing by quickly recognizing what kind of deck opponents have and guessing their likely cards or moves, and during the deck building process, by selecting cards that do well against current popular deck types at the possible expense of performance against rarer ones. Another example of metagaming would be bluffing opponents into expecting cards that you do not have, or surprising the competition with novel decks that they may not be prepared for. The secondary market of cards is heavily influenced by metagame trends: cards become more valuable when they are popular, often to the point of scarcity.

https://en.wikipedia.org/wiki/Metagaming