On the Filter Target pop-up menu, you will find an option called Property. This allows you to search for properties that are not part of the MIDI standard but rather Cubase-specific settings.
When the Property option is selected, the Condition column has 2 options: “Property is set” and “Property is not set”. Which property to look for is selected in the Parameter 1 column. The options are “muted”, “selected”, “empty”, “inside NoteExp”, and “valid VST 3”. Some examples: