Review for CardBook by Tom Leonard
Rated 5 out of 5 stars
After endless frustration with TbSync, I finally switched to CardBook. As part of the process I had to manually resolve a lot of duplicates, but ended up with seamless integration between Thunderbird, Google Contacts and my phone. If you are prepared to put in a little effort to clean up your contacts, this is a great add-on.
This review is for a previous version of the add-on (76.3).To create your own collections, you must have a Mozilla Add-ons account.