You can easily find out Test Scenarios which are not associated to any story.
Step 1 : Go to click on 'QMetry' add-on drop-down
Step 2 : Click on 'Create Test Run' button
Step 3 : Click on 'Select Using :' drop-down and you can see 'Only unassociated Test Scenarios' radio button and you will see the Test Scenarios which are not associated to any of the story.
Here is the link to help documentation.