Review for CardBook by Firefox user f2ffed
Rated 5 out of 5 stars
Very good address book, with a lot of advanced features: Merge, find duplicates, tabular view, manage many different address books, sync addresses with external service providers (Nextcloud and others). Have a look at the add-on Homepage to see all the features.
This review is for a previous version of the add-on (94.3).To create your own collections, you must have a Mozilla Add-ons account.