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

Thunderbird, Postbox

Reload Proxy

Reload Proxy

Reload the currently in use proxy.

Compatibility: Pale Moon 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 Toolbar

Toggle the Main Toolbar

Toggle the main toolbar from showing to hidden. Don't place it on the main toolbar, it is disabled then and will not work.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Update

Check For Updates

Check for updates to the currently open application.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

about:about

List and open any of the about pages

Lists all the "about" pages so that they can be opened.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Copy

Copy Selected Text

Copy selected text.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Empty Trash

Empty The Trash Folder

Empty the Trash Folder

Compatibility: Thunderbird, Postbox SeaMonkey

Hide Toolbars

Toggle visibility of all toolbars, except the main toolbar

Toggle the visibility of all toolbar, other then the main toolbar.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Restart

Restart Application

Restart the current application after installing a new extension, theme or plug-in.

There is a number of reasons you may want to restart the program your using. Though having installed an extension is the most common. This button take all the hassle and work out of it.

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