The following icons are from GNOME 2.6:

    connect.xpm (stock_connect)
    contact.xpm (stock_contact)
    delete.xpm (stock_delete)
    describe.xpm (stock_properties)
    disconnect.xpm (stock_disconnect)
    exit.xpm (stock_exit)
    lock-broken.xpm (stock_lock_broken)
    lock-ok.xpm (stock_lock_ok)
    lock.xpm (stock_lock)
    refresh.xpm (stock_refresh)

    gnus/toggle-subscription.xpm (stock_task-recurring)

    mail/attach.xpm (stock_attach)
    mail/compose.xpm (stock_mail-compose)
    mail/copy.xpm (stock_mail-copy)
    mail/forward.xpm (stock_mail-forward)
    mail/inbox.xpm (stock_inbox)
    mail/move.xpm (stock_mail-move)
    mail/not-spam.xpm (stock_not-spam)
    mail/outbox.xpm (stock_outbox)
    mail/reply-all.xpm (stock_mail-reply-to-all)
    mail/reply.xpm (stock_mail-reply)
    mail/save-draft.xpm (stock_mail-handling)
    mail/send.xpm (stock_mail-send)
    mail/spam.xpm (stock_spam)

The following icons were contributed by from Adam Sjøgren <asjo@koldfront.dk>:

    mail/preview.xpm (combining stock_mail and stock_zoom)
    mail/save.xpm    (combining stock_mail, stock_save and stock_convert) 

The following icon is from AUCTeX:

    separator.xpm (sep.xpm)


The folling icon are duplicated from Emacs 22.  They are either not present in
Emacs 21 or look different there.

    cancel.xpm
    copy.xpm
    diropen.xpm
    help.xpm
    left-arrow.xpm
    next-page.xpm
    paste.xpm
    print.xpm
    redo.xpm
    right-arrow.xpm
    save.xpm
    search.xpm