PHB, page 154. Additional information from XGE, page 81. Available in the SRD.
Gaming Set Common
If you are proficient with a gaming set, you can add your proficiency bonus to ability checks you make to play a game with that set. Each type of gaming set requires a separate proficiency. See the Tool Proficiencies entry for more information. Proficiency with a gaming set applies to one type of game, such as Three-Dragon Ante or games of chance that use dice. Components. A gaming set has all the pieces needed to play a specific game or type of game, such as a complete deck of cards or a board and tokens. History. Your mastery of a game includes knowledge of its history, as well as of important events it was connected to or prominent historical figures involved with it. Insight. Playing games with someone is a good way to gain understanding of their personality, granting you a better ability to discern their lies from their truths and read their mood. Sleight of Hand. Sleight of Hand is a useful skill for cheating at a game, as it allows you to swap pieces, palm cards, or alter a die roll. Alternatively, engrossing a target in a game by manipulating the components with dexterous movements is a great distraction for a pick-pocketing attempt. Gaming Set Activity DC Catch a player cheating 15 Gain insight into an opponent's personality 15
Cost: 1sp