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

Thunderbird, Postbox

Find

Find Text

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

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Options

Open options

Opens the Options window so you can change settings easily.

Firefox, Thunderbird and Sunbird all have a huge number of settings. Often you will find a need to change one. About to visit your banking site, so you want pop ups enabled, or what ever your current need might be. The button brings the option window to you quicker.

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

Source

View Page Source

View the page or message source code.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Delete

Delete Selected Text

Delete the currently selected item(s) or text.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Delete Junk

Delete Junk Messages

Empty the junk email folder of all junk email.

Compatibility: Thunderbird, Postbox SeaMonkey

Save

Save document as

Save the currently open document, or image to a file.

Saving a page or email for later viewing or to send to a friend is a much needed functionality, so much so that there really should be a toolbar button for it.

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

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