The media library has a feature called "media-tags". This feature can be used to add multiple tags to a a file to make it easy for you to display a specific filtered list for a single tag in the future. This is similar to using a folder.
A tag can be created as you add the file, or in the "Media Tags" section of the upload you can "Choose From Popular Tags". This allows you to select a previously created tag. You can also "edit" a file and add a tag.
If you want to setup multiple tags you can hover over the "Media" menu in the dashboard and select "media-tags". This allows you to create a series of tags to be used in the future.
Related Article: activate Media Tags Plugin