https://materialdesignicons.com/

Adding custom icon to icon control in Elementor

/**
 * Adding custom icon to icon control in Elementor
 */
function jet_add_custom_icons_tab( $tabs = array() ) {

	// Append new icons
	$new_icons = array(
		'account',
		'airplane',
		'wordpress',
	);
	
	$tabs['my-custom-icons'] = array(
		'name'          => 'my-custom-icons',
		'label'         => esc_html__( 'My Custom Icons', 'text-domain' ),
		'labelIcon'     => 'fas fa-user',
		'prefix'        => 'mdi-',
		'displayPrefix' => 'mdi',
		'url'           => 'https://cdn.materialdesignicons.com/4.5.95/css/materialdesignicons.min.css',
		'icons'         => $new_icons,
		'ver'           => '1.0.0',
	);

	return $tabs;
}

add_filter( 'elementor/icons_manager/additional_tabs', 'jet_add_custom_icons_tab' );