The Impact Analysis report shows you metadata dependencies and allows you to create entity relationship diagrams. This report is very powerful and allows you to report on over 1200 relationships within your org.
You can choose any piece of metadata, say an email template, and choose the types of metadata you'd like to compare their relationships to.
On the first tab, you will select the asset you would like to report on. You can only choose one asset at any given time.
After that, you will continue to the Filter Types tab, which is where you will choose which other metadata types you would like to compare your asset to. We have the most popular metadata types selected already to compare, but you may choose to select all metadata types to ensure you are getting all of the relationships you may need. This can be helpful if you are trying to delete anything and you are running into the Salesforce error where you can't delete the asset until all relationships are decoupled.
Once you have your chosen asset and the filter types selected, navigate to the View Dependencies tab. This will load a graph of all of your metadata dependencies.
As you can see in my example, my email template is referenced by 2 workflow alerts and it also references an object and fields. You can continue to expand elements to the left or to the right to get a full picture of all of the references that tie back to your original asset. If you want to view an easier to read version of this report, you can go to the Display Report tab.
This view can be exported as an excel or CSV as well with a right-click.
Back to the view dependencies tab, there are a lot of actions you can take when you right-click here as well.