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

Thunderbird, Postbox

Cookie Exceptions

Open the Cookie Exceptions dialog

Open the cookie exceptions dialog.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Passwords

Open Password Manager

Opens the password manager to view saved passwords

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Toolbar Display

Change Toolbar Icon Size and Display Mode

Set the toolbar icon size as either large or small, and the button display mode between icons, icons and text, or text only.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Page Fonts

Toggle between the default and the sites fonts

Toggle between the use of the fonts used by the site and those that are set as the default.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Select All

Select All Text

Select all the text in the current text box, web page, etc.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Menu

All menus

Show all the menus in a single menu.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Minimize

Minimize current window

Minimize the current window.

I hate popups that don't show the minimize button on the window itself. This has been my solution. Also when I use full screen mode, and then want to minimize the window, this again this comes in useful.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Customize Toolbar

Customize toolbar, add or remove buttons etc.

Open the customize toolbar window to add or remove items from your toolbar.

The customize Toolbar window is where every button from this extension and others like it get placed for you to then move to your toolbar. Creating the perfect set up is always a moving target that is never quite achieved, but this will make it a little quicker to get there.

Compatibility: Pale Moon Thunderbird, Postbox SeaMonkey

Delete

Delete Selected Text

Delete the currently selected item(s) or text.

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