http://www.pentagon-ai.army.mil/images/icons/buttons/buttons.html
Buttons for all occasions is what you will find in this large collection of images provided by The U.S. Army Artificial Intelligence Center. Intended for use on in house Web pages, these button icons are provided for public use also. The icons provide numerous images of text, numerals, and assorted shapes. Several sizes are also made available. Use the filenames and locations provided to download the images you need.