One can find rectangular decks, round decks, and even 'crooked' decks. There are a variety of card decks available today, from miniatures less than an inch in height, to oversized cards sometimes used as shooting targets. Card reverses have also been used to advertise a wide array of products, including soft drinks, airlines, beer, sports teams, soup, motorcycles, and more. At one time, blank card backs were common. There is no standard back or card reverse, so these designs vary widely. Generally, there is no ranking system for the various suits in a deck of cards, however, ranks are assigned to suits in certain games. For example, hearts, leaves, bells, and acorns are found on German cards shields, 'roses,' bells, and acorns on Swiss cards and coins, cups, swords, and cudgels on Spanish cards. In decks from other countries, suits are often represented by different pips.

Suits are identified by symbols or 'pips,' which on an English deck consist of the familiar spades, clubs, diamonds, and hearts. Many games also make use of 'stripped' decks in which certain cards are removed for play. Decks also often include two 'joker' cards that are sometimes included for game variations. The appearance of the face cards has become fairly standardized since cards have been mass-produced. Card values in each suit include numbered cards of two through ten, an ace, and three 'face' or 'court' cards consisting of a jack, queen, and king. The standard deck in use in the United States, and the most commonly used deck worldwide, consists of fifty-two cards in four suits of thirteen cards each. It is surprising to many that what is considered the 'standard' deck of playing cards varies around the world. A few simple card games involve pure chance, with winning and losing depending on who gets the 'best' and 'worst' collection of cards at distribution, while most card games involve strategy in that players can choose to add cards to their hands, discard some and add others, or make some other wise attempt to improve their odds of winning through decision making. Playing cards can be regarded as randomization devices, similar to dice or roulette wheels, in that they are shuffled (randomized) prior to their distribution to players. Playing cards are used around the world in games that range from simple children's activities, to high-stakes gambling in casino games, and world championships in forms such as bridge.

Most popular card games in the world