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

Thunderbird, Postbox

Cookie Manager

Opens the cookie manager for the current web page.

Opens the cookie manager for the current web page. On middle click opens in a new tab.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Exit

Exit Application

This button not only closes the current window, but every one that the current application may have open. It is a lot quicker than finding all windows and closing them one at a time.

Finished browsing or reading all your emails, left lots of windows open? Don't want to have to shut them all one at a time? This little button can close them all, with out you having to do it all.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Menu

All menus

Show all the menus in a single menu.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Find

Find Text

Open the find bar to find a word in the current page.

Compatibility: Pale Moon 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

Work Offline

Toggle work offline

Toggle Work Offline and Work Online.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Edit Menu

Show the edit menu

Show the edit menu.

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

Passwords

Open Password Manager

Opens the password manager to view saved passwords

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