There are tons of extensions on the Visual Studio Gallery, but most of them are for general developers using Visual Studio, or for some specific development technology (Web, etc.). However, there are some extensions that are specific to Visual Studio Extensibility (VSX) developers. The most known is the Extensibility Tools extension by Mads Kristensen, but there are also little gems from other Microsoft members.
I found a reference to this one by Paul Harrington that I didn’t know in a thread of the MSDN VSX forum:
“Provides real-time diagnostics output of various sub-systems within Visual Studio. Access the toolwindow from the Help menu.”
It supports VS 2012, 2013 and 2015. Despite the name, it’s an extension to diagnose Visual Studio subsystems such as:
- Document Tab Well
- File Change Service
- Main Frame Data Model
- Navigation History
- OLE Component Manager
- Package Manager
- Running Document Table
- Scrollbar Theming
- Selection and UIContext
- Task Scheduler Service
If your extension interacts with one of those subsystems, you can find it very useful. Furthermore, it is extensible so your own extension can provide diagnostics on that tool using the IVsDiagnosticsProvider interface.