Functional icons perform an action or navigates a user to a page to perform the action. These icons have state: enabled, disabled, hover and selected.
Never use functional icons as a way to beautify a page or uncluttered a form --use qualifier icons instead. By design, functional icons are subdued to give rise to page content over page functions (i.e., chrome). Over-populating the page with functional icons for decorative purposes defeats the goal of functional icons
Functional Icons are primarily 16x16 pixel size icon with a label.
Please note that the icon samples below are not a reflection of content that would actually be placed in a tool-bar. It's a representation of the various combinations of functional icons that are placed in a menu, button with text and stand alone icons. Iconic buttons can be also used but are not encouraged.