A searchable guide to the complete WordPress Icon Library (@wordpress/icons) package from Gutenberg.
import { Icon, plus } from '@wordpress/icons';
<Icon icon={plus} />
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M11 12.5V17.5H12.5V12.5H17.5V11H12.5V6H11V11H6V12.5H11Z"></path></svg>
plus – WordPress Icon Library