The following information has been taken out of IBM's Warp 3 Toolkit documentation. The XFolder class has been omitted here. OS/2 Warp 4 adds a few more classes, which are in part shown here; depending on other WPS-aware software installed on your system, even more classes might be available for certain document types.

Classes that make sense to create objects with using the provided NEWOBJ.CMD are highlighted. Be careful with other classes, results may be unpredictable. 

       WPObject
         ├── WPAbstract
         │     ├── WPClock
         │     ├── WPCountry
         │     ├── WPDisk
         │     ├── WPKeyboard
         │     ├── WPLaunchPad
         │     ├── WPMouse
         │     ├── WPPalette
         │     │     ├── WPColorPalette
         │     │     ├── WPFontPalette
         │     │     └── WPSchemePalette
         │     ├── WPPower
         │     ├── WPPrinter
         │     │      └── WPRPrinter
         │     ├── WPProgram
         │     ├── WPShadow
         │     │      └── WPNetLink
         │     ├── WPShredder
         │     ├── WPSound
         │     ├── WPSpecialNeeds
         │     ├── WPSpool
         │     ├── WPSystem
         │     └── WPWinConfig
         ├── WPFileSystem
         │     ├── WPDataFile
         │     │      ├── WPBitmap             3)
         │     │      ├── WPHtml               2)
         │     │      ├── WPIcon
         │     │      ├── WPMet
         │     │      ├── WPPif
         │     │      ├── WPPointer
         │     │      ├── WPProgramFile
         │     │      │      └── WPCommandFile
         │     │      ├── WPUrl                2)
         │     │      └── WebExplorer_Url      1)
         │     └── WPFolder
         │            ├── WPDesktop
         │            ├── WPDrives
         │            ├── WPHost               2)
         │            ├── WPHvManager          2)
         │            ├── WPMinWinViewer
         │            ├── WPNetgrp
         │            ├── WPNetwork
         │            ├── WPRootFolder
         │            ├── WPServer
         │            ├── WPSharedDir
         │            ├── WPStartup
         │            ├── WPUrlFolder          2)
         │            └── WPTemplates
         └── WPTransient
               ├── WPDevice                    2)
               │     ├── WPDevAudio            2)
               │     ├── WPDevBus              2)
               │     ├── WPDevCDRom            2)
               │     ├── WPDevCPU              2)
               │     ├── WPDevDiskette         2)
               │     ├── WPDevDisplay          2)
               │     ├── WPDevHarddrive        2)
               │     ├── WPDevKeyboard         2)
               │     ├── WPDevMemory           2)
               │     ├── WPDevMouse            2)
               │     ├── WPDevParallel         2)
               │     ├── WPDevPeriph           2)
               │     ├── WPDevSerial           2)
               │     ├── WPDevTape             2)
               │     └── WPDevTimer            2)
               ├── WPJob
               ├── WPPdr
               ├── WPPort
               └── WPQdr
Notices:

1) This is not a standard WPS class and might not be present on every Warp 3 system.

2) This class is available only on OS/2 Warp 4.

3) In Warp 4, WPBitmap is a subclass of WPImageFile, which is in turn a subclass of WPDataFile.