Review for Expression Search / GMailUI by George
Rated 5 out of 5 stars
This is a great add-on. The way it filters emails and the many ways of searching are all significantly more useful than Thunderbird's built-in search, in my opinion. I am praying for it to be updated for the newer versions of T-bird! I'm keeping my Thunderbird old in order to keep using this add-on.
To create your own collections, you must have a Mozilla Add-ons account.