You can download Tk::ToolBar which comes with a decent number of button images. It has what you need, and there is a bundled Perl program that allows you to see all the images. When you instantiate a ToolBar widget, it loads all of those images, so you can use them anywhere in your program. If you don't need a toolbar widget, you can do this:
in reply to Button graphics for Tk
This will still call the subroutine that loads all the images, but will destroy the toolbar widget along the way.
If you don't want that route, you can download the same images directly from the ICONS project.