Catering is one service where you are likely to prefer a local supplier. Very few persons would want to bring a caterer from some other country and risk a party disaster. Corporate parties might go for specialized and reputed catering organizations headquartered elsewhere. Even they might often find it necessary to go for local caterers when time is short.
Catering directories generally focus on the final consumers, listing vendors by food categories such as beverages, chocolate fountain, fruit, juice, etc; and by supplier categories like food vendors, caterers, mobile vendors, party organizers, restaurants, party shops, etc. There might also be sections on Health & Safety and Catering Tips.
Another catering directory might arrange vendors by such categories as caterers, event venues, entertainment, photography, transportation, wedding, event planners, florists, etc.
All are likely to provide the option to narrow down the lists to locations you select, such as a city or area.
Some might collect information such as number of guests, event type, services required (such as food, servers, liquor, chocolate fountain, decorations, tables/chairs,...