A searchable guide to the complete WordPress Icon Library (@wordpress/icons) package from Gutenberg.
import { Icon, fullscreen } from '@wordpress/icons';
<Icon icon={fullscreen} />
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M4.2 9h1.5V5.8H9V4.2H4.2V9zm14 9.2H15v1.5h4.8V15h-1.5v3.2zM15 4.2v1.5h3.2V9h1.5V4.2H15zM5.8 15H4.2v4.8H9v-1.5H5.8V15z"></path></svg>
fullscreen – WordPress Icon Library