A searchable guide to the complete WordPress Icon Library (@wordpress/icons) package from Gutenberg.
import { Icon, envelope } from '@wordpress/icons';
<Icon icon={envelope} />
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path fill-rule="evenodd" clip-rule="evenodd" d="M3 7c0-1.1.9-2 2-2h14a2 2 0 0 1 2 2v10a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V7Zm2-.5h14c.3 0 .5.2.5.5v1L12 13.5 4.5 7.9V7c0-.3.2-.5.5-.5Zm-.5 3.3V17c0 .3.2.5.5.5h14c.3 0 .5-.2.5-.5V9.8L12 15.4 4.5 9.8Z"></path></svg>
envelope – WordPress Icon Library