These are a ready make selection of some of the most popular buttons from the Custom Toolbar Button Maker

Thunderbird, Postbox

New Event

Add a new event to the calendar.

Add a new event into the calendar.

Compatibility: Thunderbird, Postbox SeaMonkey

New Task

Add a new task to the calendar.

Add a new task to the calendar.

Compatibility: Thunderbird, Postbox SeaMonkey

Previous Message

Get Real Previous Message

Get the previous message. Unlink the default Thunderbird buttons this just go to the previous in the list, or if shift is pressed, the previous unread.

Compatibility: Thunderbird, Postbox SeaMonkey

Read

Read Message

Open the currently selected message in Thunderbird.

Compatibility: Thunderbird, Postbox SeaMonkey

Remote Content

Set the exceptions for what remote content can load.

Opens the window to set exceptions for the loading of remote content

Compatibility: Thunderbird, Postbox SeaMonkey

Tasks In View

Toggle Tasks in View

Toggle the Task in View panel in Sunbird.

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Tasks

Toggle the task bar

Toggle the task bar between visible and hidden.

Compatibility: Thunderbird, Postbox SeaMonkey