The “Site Content and Structure” reports are a great way of finding files which are pending approval or checked out but I just realised you can create your own reports.
If you have never seen these reports before:
Go to site settings –> Site Administration –> Content and structure
But you can create you own reports by going to “View all site content”
Under lists –> Content and Structure Reports
Here you can see all the reports available from C & S as well as the CAML that makes these reports.