You can add frequently used actions to the quick access toolbar by right-clicking on the action button (for e.g. the "Items in room" button) then select "Add to Quick Access Toolbar":

The "Items in room" button will henceforth be accessible on the right side of the upper toolbar:

Room Reference

Usually when working with the Plug-In you are working with Revit Rooms or Spaces, meaning you may need to frequently select Rooms or Spaces within Revit to access information such as the Revit Room / Space parameters, Family instances in Revit Rooms / Spaces, Item occurrences in dRofus Rooms, etc. One way to select the Rooms or Spaces in the model easily is to activate the Room or Space Reference respectively. To do this open the Visibility / Graphics Overrides (shortcut "v"+"g") or View Template (if applied) settings, then under Rooms or Spaces, activate the sub section "Reference":