The Cakewalk Plug-in Manager in SONAR allows for custom plug-in menu layouts. This allows you to organize your plug-ins into folders and categories to your liking. By default, SONAR installs and configures itself to use the "X3 Producer Effects", "X3 Studio Effects", or "X3 Effects" menu layout (depending on your version). This plug-in menu layout defaults to showing all of the plug-ins shipped with your version of SONAR.

If you have additional plug-ins you are trying to view, you can switch your menu layout to the "Default All Plug-ins" menu layout. This option will dynamically build a list of all plug-ins installed on your system so you can access them from the menus.

More information on creating custom plug-in menu layouts can be found by going to Utilities > Cakewalk Plug-in Manager and then clicking on the Help button.