There are a set of icons, which could be used by Set(icons ...) command:

Icon	Name	Icon	Name	Icon	Name	Icon	Name	Icon	Name
	bookmark		click_icon		colorize		configure		connect_creating
	connect_established		connect_no		default		down		exit
	editdelete		edit		exec		file		fileclose
	fileexport		find		fit		flag		folder
	forward		fullscreen		hash		icon		info
	kill		launch		minimize		minus		mute
	next		no		ok		pause		play
	plus		previous		question		question-x2		rewind
	refresh		star		stop		unmute		up
	view_text		view_tree		vol_down		vol_up