Here are some of the common category strings used for events and properties in the .NET Framework:
WinForm Event Categories
Action, Appearance, Asynchronous, Behavior, Data, Display, Drag Drop, Focus, Key, Layout, Mouse, Private, Property Changed
WinForm Property Categories
Accessibility, Appearance, Behavior, Colors, Data, Display, Drag Drop, Focus, Items, Layout, Window Style
Web Event Categories
Action, Behavior, Data
Web Property Categories
Accessibility, Action, Appearance, Behavior, Cache, Control, Data, Databindings, Layout, Links, Misc, Navigation, Paging, Styles, Validation, Web Part, Web Part Appearance, Web Part Behavior
Data Event Categories
Action, Data, Fill, InfoMessage, StateChange, StatementCompleted, Update
Data Property Categories
Advanced, Behavior, Context, Data, Fill, Initialization, Mapping, Named ConnectionString, Notification, Pooling, Replication, Schema, Security, Source, Update, XML
Common Event and Property Categories
Asynchronous, Behavior, Misc