Deck building is the process of creating a customized set of cards for use in various card games, such as Magic: The Gathering or Hearthstone. Players select cards from their collection to form a deck that reflects their strategy and play style. The goal is to create a balanced and effective combination of cards that can compete against other players' decks. In deck building, players consider factors like card synergy, mana cost, and win conditions. A well-constructed deck can enhance a player's chances of winning by allowing them to execute their strategies more effectively during gameplay.