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

Thunderbird, Postbox

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

Rewrap

Rewrap

Rewraps the message text

Compatibility: Thunderbird, Postbox SeaMonkey

Tasks In View

Toggle Tasks in View

Toggle the Task in View panel in Sunbird.

Compatibility: Thunderbird, Postbox SeaMonkey

Threads with Unread

View Threads With Unread

View only the threads in the current folder that have unread messages.

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Tasks

Toggle the task bar

Toggle the task bar between visible and hidden.

Compatibility: Thunderbird, Postbox SeaMonkey

Unread Threads

View Unread Threads

View threads that you have not read yet.

Compatibility: Thunderbird, Postbox SeaMonkey

Watched Threads with Unread

View Watched Threads With Unread

View watched threads that have unread messages in them.

Compatibility: Thunderbird, Postbox SeaMonkey