From the introduction: Additional Fight Clubs: Detailed here are three additional Fight Clubs: Arena Royale, Bloodhound Bruisers, and Salt & Vinegar. You may choose one of these Fight Clubs when you reach 3rd level as a pugilist and gain additional features from that Fight Club at 6th, 11th, and 17th level. Despite the name, fight clubs are not formal fraternities or sororities but collections of pugilists who, by training or happenstance, share a similar style. In some D&D worlds, fight clubs can tell you a lot about where a person comes from while in others there are representatives of many fighting styles in all metropolitan areas. User summary: See also The Pugilist: A Streetfighting Class with Swagger to Spare (5e).