Activating this plugin will make the search search media attachment as well as posts or pages.

This would allow you to share resources by just uploading sensibly named files.

For example this blog has several images of ferrets and a pdf named ferret uploaded to the media library. They are not in any posts or pages.

But you find them if you search for ferret which picks up the names of the files or Mustelidae which will find text in the description and pick up a few more members of the weasel family.