Date Time Formatter

Shows relative date-time in the column.
Note: you need to click "Select columns to display" and then -> "Relative Date/Time"

All Events

Define your own time ranges for appointment searches

ElsHelp

Extension for ElSchool diary

iCanban - Kanban with ICAL

Allday Tasks

Thunderbird lacks the ability to create and manage allday tasks. This add-on adds these capabilities.

Message Links 4 events

Allows to use links to messages in the description field of events and task

Calendar/Project Tools: Gantt-/Year View, Planner

*Display Gantt View and Year View
*Task Time Planning: daily, distribute your open tasks into open time slots.
*Show parent/child relationships for tasks

Outlook Calendar - Quick Access

This extension adds a simple button to your Spaces toolbar that opens in a new tab, providing you with one-click access to Outlook Calendar.

Create Calendar events from mail content

This plugin offers to create new events based on the email subject and content

Date on Thunderbird Requires Restart

在thunderbird statusbar显示年月日

Gantt View Requires Restart

Gantt Chart view for Sunbird/Lightning

More Snooze

This add allow to customize the snooze delay when snooze popup appears (lightning required).

Montezooma Requires Restart

Montezooma is a Thunderbird Addon that adds zooming functionality to windows.

Purge Events Plus Requires Restart

Purge events from Sunbird and Lightning files and thereby cleanes the calendar

Reply Monitor Requires Restart

**This is NOT COMPATIBLE with Thunderbird 31 or newer versions**
Keep track of your emails and replies (Lightning is required).
Note: the name of this add-on has been changed to Reply Monitor because the previous name is a registered trademark.

SanRockstar Requires Restart

Music

StormCows Requires Restart

Allows two-way access between Remember The Milk and calendar events or todo items.

MiniWebView Sidebar Requires Restart

Sidebar that shows a single web page. This allows Thunderbird to be augmented with any user-supplied or third-party web page. The screenshot shows an example - I use my own custom web page to present my Google Calendar in my preferred format.

OBM Connector Requires Restart

OBM Lightning Calendar and addressbooks connector

DM Sync Requires Restart

This plugin allows you to synchronize addressbooks and contacts stored on the DM mail server