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

Thunderbird, Postbox

Options Menu

Show the options menu in the compose mail window.

Install Options Menu

Download Options Menu

Compatibility: Thunderbird, Postbox SeaMonkey

Plain Text Paste

Paste text into Thunderbird without any formatting.

Install Plain Text Paste

Download Plain Text Paste

Compatibility: Thunderbird, Postbox SeaMonkey

Reply to Sender Only

Reply only to the sender of the email.

Install Reply to Sender Only

Download Reply to Sender Only

Compatibility: Thunderbird, Postbox SeaMonkey

Rewrap

Rewraps the message text

Install Rewrap

Download Rewrap

Compatibility: Thunderbird, Postbox SeaMonkey

Tasks In View

Toggle the Task in View panel in Sunbird.

Install Tasks In View

Download Tasks In View

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Starred

Toggle the starred status (look for the star next to the message).

Install Toggle Starred

Download Toggle Starred

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Tasks

Toggle the task bar between visible and hidden.

Install Toggle Tasks

Download Toggle Tasks

Compatibility: Thunderbird, Postbox SeaMonkey