Contacts.app: How to merge duplicate contacts? The Apple article If you see duplicate contacts after setting up iCloud Contacts, suggest using the Card > Look for Duplicates option. However I can clearly see three or four contacts all with the same exact details in the list (e.g. for each contact, there are 3 or 4 duplicates of it), but the "Look for Duplicates" option simply can not. 

Is there a way to select, by hand if I have to, the contacts and moosh them together into just one contact?
This is in macOS 10.12.6 and Contacts 10.0:

Select the cards you wish to merge.
Then in the Card menu, select "Merge Selected Cards."