These are a ready make selection of some of the most popular buttons from the Custom Toolbar Button Maker
Install
Installing Extensions and particularly themes that you have downloaded can be quite a trick. This button makes the process simple and hassle free.
Bookmark Menu
The Bookmark Menu made with an icon, uses less toolbar space and looks much nicer.
Gmail
Gmail, Google's massively popular web based email. Checking if you have a new email becomes an often repeated task. This button serves as a second "home page" button, bring you to your email quicker and will less hassle.
Print Preview
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.
Bookmark Manager
Anyone who bookmarks lots of page will soon find they need to sort them into some kind of order. The bookmark manager button allows quick access to the bookmark manager window where bookmarks can be moved, edited or deleted.
Translate
Translate current page to your preferred language using the Google Translation service.
Full Screen
Toggle the window to full screen mode, so you can view as much of the current page as possible.
Bookmark Page
Bookmarks are the heart of the web browser, remembering where the great page your saw the other day can be quite hard, so you bookmark it. Having a convenient button to quicken the process just makes so much sense.
Add-ons
This being the most downloaded button I have made speaks for itself. 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 black to go. Being able to access this quickly is a necessity for many.
Bookmark Toolbar
Show/Hide to Bookmark Toolbar.