A game is any activity in which playing cards are used as the primary way for people to interact with each other. There are infinite games and many families of games (like poker).
Even though a few games use standard decks and standardized rules and are played at international tournaments, the vast majority of games are played by individuals, and their practices vary by region, culture, and player.
Card games often use a deck or pack of cards of the same size and shape. There is a front and a back to each card. Typically, the backs of playing cards need more specificity.
The cards’ essences may be unique, or they could be duplicates. Everybody knows how a deck is synthesized. Sometimes a single pack or shoe is formed by rearranging several decks.
Most modern games use specialized decks, often with many cards that might include both number and activity cards. Most people consider games like this a fun diversion when playing other table games.