The following icons are from GTK+ 2.x:

    close.xpm copy.xpm cut.xpm help.xpm home.xpm
    index.xpm jump_to.xpm left_arrow.xpm new.xpm open.xpm
    paste.xpm preferences.xpm print.xpm right_arrow.xpm save.xpm
    saveas.xpm search.xpm spell.xpm undo.xpm up_arrow.xpm

    back_arrow.xpm and fwd_arrow.xpm are slightly modified undo and redo.

They are not part of Emacs, but distributed and used by Emacs.
