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

Thunderbird, Postbox

Source

View Page Source

View the page or message source code.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Status Bar

Toggle The Status Bar

Toggle the status bar from hidden to shown. Hide it to get the most out of your screen space, and show it when it really needed.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Switch Profile...

Change Profile that you are currently using.

Switch the Profile that you are currently using.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Tasks In View

Toggle Tasks in View

Toggle the Task in View panel in Sunbird.

Compatibility: Thunderbird, Postbox SeaMonkey

Themes

Open Themes Manager

Open the themes manager to change you theme or install a new one.

Compatibility: Pale Moon 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 menu bar

Toggle the menu bar

Toggle the menu bar. Don't put this button on the menu bar!

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Toggle Read

Toggle Message Read Status

Toggle the Read status of the currently selected message.

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Starred

Toggle Starred Status

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

Compatibility: Thunderbird, Postbox SeaMonkey

Toggle Tasks

Toggle the task bar

Toggle the task bar between visible and hidden.

Compatibility: Thunderbird, Postbox SeaMonkey