How to find duplicates from message "It looks as if duplicates exist for this Lead"

Hello,

We have a couple of matching and duplicate rules for the Lead and Account objects.

Regularly, I can see this message on top of a Lead record.

I know how to merge duplicates using Duplicate Record Sets but that's for duplicates I'm aware of.

Is there a way to identify all the records that are recognised as duplicates, i.e. the ones I haven't spotted yet?

What I found online is suggestions using a custom report but the report only shows me the duplicates I've already identified and merged, not the ones I don't know of. 

(PS: we're on the Enterprise edition.) #Duplicates #Duplicate Record