A little "More"... Rated 4 out of 5 stars

CustomButtons2 is what GreaseMonkey or Stylish are: simply essential for customization. Yet it's not "perfect"... YET!...

16x16 small icons, non-square buttons, inability to delete buttons unless added to toolbar, small (current) repository of buttons and similar things make CustomButtons2 need some polishing to be perfect...

Until then for simplicity, bigger icons and completeness you are advised to use "Toolbar Buttons" and/or "Toolbar Extras" addons for Firefox...

This review is for a previous version of the add-on (3.0.1). 

re: A little "More"...

Our Icon size is determined by the icon chosen by the button author and is not fixed. They can be square or rectangular based the icon used.

Firefox provides no means to select a custombutton from the "Customize palette" that I am aware of. Deleting a button from a toolbar ensures every opportunity is provided to the operator to select the correct button to delete.

There are approx. 400 buttons residing on our buttons database on http://custombuttons2.com./en-us
More are being added as authors create them.