Players of deck/pool building games start each game with a pre-set group of cards (or, in the case of Quarriors, a pool of dice). Throughout the course of the game, players add to and/or change their deck by buying cards from a catalog of cards that is accessible to all players. Most deck/pool building games have a form of currency (often in the form of the cards or dice the players can purchase) that they use to buy new cards. Once purchased, these new cards are then integrated into the player’s deck or pool and grant the player new options of play.
Note: the deck/pool building game mechanic refers to something that happens during the playing of a game, not the modification of cards prior to play.