Final Cut Pro X: Smart Collection
When you search for clips in an event using the Filter window, you can save your results by creating a new Smart Collection that gathers clips matching the search criteria. Whenever a new clip that matches the Smart Collection’s search criteria is brought into the event, the new clip is automatically added to the Smart Collection.
Clips that appear in Smart Collections are not duplicates. Smart Collections filter clips in an event to help you focus on the clips you need to use for a specific task.