Extensions very useful for customer support with Thunderbird
Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
FoxClocks shows times around the world - or just your local time - at the bottom of your browser. It deals with daylight saving time so you don't have to.
Search and remove messages which are the same as other messages in your mail folders (referred to as duplicates or dupes).
Select all the mails in a directory sent by the selected authors.
Collections are groups of related add-ons that anyone can create and share.Explore Collections