Code to add a count bubble of draft posts to the Posts menu.

add_draft_count.php

// Add a count of draft posts to the Posts menu
function zedejose_add_draft_count() {
	
	global $menu;

	$count_posts = wp_count_posts();
	$draft_posts = $count_posts->draft;

	$menu[5][0] = $menu[5][0] . '<span class="update-plugins count-2"><span class="plugin-count">' . (int)$draft_posts . '</span></span>';
}

add_action( 'admin_menu', 'zedejose_add_draft_count' );