Re-order WordPress dashboard admin menu by top-level page slugs

re-order-wp-admin.php

<?php

// Reorder admin menu
add_filter( 'custom_menu_order', '__return_true' );
add_filter( 'menu_order', 'my_theme_reorder_admin_menu' );

function my_theme_reorder_admin_menu() {
	return array(
		'index.php',
		'edit.php?post_type=page',
		'edit.php',
		'edit.php?post_type=testimonials',
		'edit.php?post_type=portfolio',
		'separator1',
		'themes.php',
		'admin.php?page=gf_edit_forms',
		'users.php',
		'upload.php',
		'plugins.php',
		'tools.php',
		'options-general.php',
		'separator2',
	);
}