Review for CardBook by Styles
Rated 5 out of 5 stars
Fantastic Addon. It broke on TB v78.2.2 but realized all I had to do to get it work again (contacts weren't coming up in autocomplete during compose) was to click the checkbox in cardbook preferences (general tab) to make it Unique Source for contacts.
This review is for a previous version of the add-on (51.7).To create your own collections, you must have a Mozilla Add-ons account.