This collection example demonstrates search criteria that are not published (Not visible by users not logged in) A good way to find out what should be published but isn't.
This example assumes you have a basic knowledge of collections. Only the search criteria is demonstrated. If you need to learn about creating a collection you can read about it here.
Unpublished Pages Example:
Unpublished Events Example:
As you can see by Selecting Type listed under Metadata heading and then selecting Matches Any of a blank field will open a drop-down with many Items you can select from such as Event, Page, News Item just to name a few. You can add more than one item to look for more unpublished items.