Media Cleaner is a tool that detects unused and useless files from your WordPress. It cleans clean your Media Library and your Uploads Directory. You can choose to check your Media Library or your Uploads Directory. Then the plugin will check if the file (or files, in the case of a media) is used anywhere in your WordPress install depending on the options you have chosen.
Demo: https://meowapps.com/plugin/media-cleaner/