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

Thunderbird, Postbox

New Task

Add a new task to the calendar.

Add a new task to the calendar.

Compatibility: Thunderbird, Postbox SeaMonkey

Next Message

Get Real Next Message

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

Compatibility: Thunderbird, Postbox SeaMonkey

Plain Text Paste

Paste Text With No Formatting

Paste text into Thunderbird without any formatting.

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

Tasks In View

Toggle Tasks in View

Toggle the Task in View panel in Sunbird.

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Read

Toggle Message Read Status

Toggle the Read status of the currently selected message.

Compatibility: Thunderbird, Postbox SeaMonkey