Search all content fields with "find content" module instead of title
Your best option is to use the Administration views module and edit the view to suit your needs. Edit the view with an exposed search filter.

Replaces administrative overview/listing pages with actual views for superior usability.

Features


  Filter all administrative views via AJAX. Perform any kind of
  bulk/mass operations on items in administrative views. Filter content
  by title, node type, author, published status, and/or vocabulary.
  Filter comments by title, author, node title, or published status.
  Filter users by name, ban/blocked status, or user roles.
  *Note: If you are upgrading from an older version of Administration views and the default views have been overridden (saved in the
  database) you could encounter issues or not see any new changes unless
  you revert these views, so the default in-code views are used. This
  can be done in the views UI listing or using drush (drush cter
  views_view --module=admin_views)