A searchable guide to the complete WordPress Icon Library (@wordpress/icons) package from Gutenberg.
import { Icon, addSubmenu } from '@wordpress/icons';
<Icon icon={addSubmenu} />
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M2 12c0 3.6 2.4 5.5 6 5.5h.5V19l3-2.5-3-2.5v2H8c-2.5 0-4.5-1.5-4.5-4s2-4.5 4.5-4.5h3.5V6H8c-3.6 0-6 2.4-6 6zm19.5-1h-8v1.5h8V11zm0 5h-8v1.5h8V16zm0-10h-8v1.5h8V6z"></path></svg>
addSubmenu – WordPress Icon Library