Two interfaces that are implemented by Visual Basic are identified here for component categories. It is not expected that controls should require these categories as it is possible for controls to offer alternative functionality when these are not available.
The IVBFormat interface allows controls to better integrate into the Visual Basic environment when formatting data.
CATID - {02496840-3AC4-11cf-87B9-00AA006C8166} CATID_VBFormat
The IVBGetControl interface allows a control to enumerate other controls on the VB form.
CATID - {02496841-3AC4-11cf-87B9-00AA006C8166} CATID_VBGetControl