where are the icons for Gizmos.DrawIcon?

which icons are available for Gizmos.DrawIcon / where are they located?

As per the docs:

The icon's path can be found in the Assets/Gizmos folder or in the Unity.app/Contents/Resources folder.

I’m using Windows 7 and it worked when I created a “Gizmos” folder inside the “Assets” folder ( "Assets\Gizmos" ) and threw all the icon images in “Gizmos”.

You can’t use built-in gizmos in code. A workaround is to set the gizmo for a script component. That gizmo will be set to whatever object attached to.

I'm using the OS X version, and found I need to create a Gizmos folder in the Assets directory (through the Unity interface). Then I can drop in any icons I want to use for gizmos and Unity will find them.