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

Thunderbird, Postbox

Add-ons

Open Add-ons Manager

Opens the Add-ons window to perform tasks on your installed Extensions, Themes, Plug-ins and Language packs.

The Add-on's window allows the installation and management of all your extensions and themes. If you need an update, change a setting, swap themes or enable/disable an add-on the Add-ons' window is the place to go. Being able to access this quickly is a necessity for anyone that uses even a handful of add-ons.

The button also contains a drop down menu that allows you to install add-ons, open the add-ons window to the extension or themes tab, or set which websites can install addons.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

about:config

Open about:config to change settings

Open about:config to change hidden settings that cannot be edited from the Options window.

All Mozilla based programs have settings that can not be changed in the options window. These hidden settings are all reveled in the about:config where anything can be changed or reset.

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

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

Print Preview

Open Print Preview

Open the Print Preview to view a page before printing it.

Paper costs money (and trees) so it is worth checking what the page looks like before you print it. Though it has always amazed me just how much the button gets downloaded.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Redo

Redo Last Change

Redo the late change.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Undo

Undo Last Change

Undo last change/action.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

About

About

Open the about window. Useful for checking exactly what version you have installed.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Free Memory

Free Unused Memory

Free unused memory that Firefox is currently using.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

about:plugins

Open about:plugins to view installed plugins

Open about:plugins to view installed plug-ins.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey