| ConstStringTable | Constant unicode string table |
| FReleaser | Release an interface using automatic object (obsolete) |
| FUID | Handling 16 Byte Globaly Unique Identifiers |
| FUnknown | The basic interface of all interfaces |
| FUnknownPtr< I > | FUnknownPtr - automatic interface conversion and smart pointer in one |
| FVariant | A Value of variable type |
| IAttributes | Object Data Archive Interface |
| IAttributes2 | Extended access to Attributes; supports Attribute retrieval via iteration |
| IBStream | Base class for streams |
| ICloneable | Interface allowing an object to be copied |
| IDependent | A dependent will get notified about changes of a model |
| IErrorContext | Interface for error handling |
| IPersistent | Persistent Object Interface |
| IPlugFrame | Callback interface passed to IPlugView |
| IPluginBase | Basic interface to a Plug-in component |
| IPluginFactory | Class factory that any Plug-in defines for creating class instances |
| IPluginFactory2 | Version 2 of class factory supporting PClassInfo2 |
| IPluginFactory3 | Version 3 of class factory supporting PClassInfoW |
| IPlugView | Plug-in definition of a view |
| IPtr< I > | IPtr - Smart pointer template class |
| ISizeableStream | Stream with a size |
| IString | Interface to a string of variable size and encoding |
| IStringResult | Interface to return an ascii string of variable size |
| IUpdateHandler | Host implements dependency handling for plugins |
| OPtr< I > | OPtr - "owning" smart pointer used for newly created FObjects |
| PClassInfo | Basic Information about a class provided by the Plug-in |
| PClassInfo2 | Version 2 of Basic Information about a class provided by the Plug-in |
| PClassInfoW | Unicode Version of Basic Information about a class provided by the Plug-in |
| PFactoryInfo | Basic Information about the class factory of the Plug-in |
| UString | UTF-16 string class without buffer management |
| UStringBuffer< maxSize > | UTF-16 string with fixed buffer size |
| ViewRect | Graphical rectangle structure |