gtk:container, gtk:widget, gtk:buildable, gobject:object, common-lisp:standard-object, common-lisp:t

gtk:action-bar, gtk:alignment, gtk:button, gtk:combo-box, gtk:event-box, gtk:expander, gtk:flow-box-child, gtk:frame, gtk:handle-box, gtk:menu-item, gtk:overlay, gtk:popover, gtk:revealer, gtk:scrolled-window, gtk:search-bar, gtk:stack-sidebar, gtk:tool-item, gtk:viewport, gtk:window

The gtk:bin widget is a container with just one child. It is not very useful itself, but it is useful for deriving subclasses, since it provides common code needed for handling a single child widget.

Many GTK widgets are subclasses of the gtk:bin class, including the gtk:window, gtk:button, gtk:frame, or gtk:scrolled-window classes.