Here are some new categories that I made up for my favorite LEGO theme, City.
Transit[]
60050 City Bus
60051 Transit Worker 4-Pack
60052 Bus Station
60053 Rapid Transit
60054 Commuter Rail
60055 Light Rail
60056 Metro Station/with Parking Garage
60057 Commuter Rail Station
60058 Light Rail Station
60059 Work Train
Military[]
60060 Military Base
60061 Tank
60061 Army Transport Bus
60062 HUMVEE
60063 Jeep
60065 Army Men 4-Pack
Great Building[]
60066 School
60067 Grocery Store
60068 Pizzeria
60069 Thrift Store
60070 Post Office
60071 City Services 4-Pack