Add link to WordPress Plugins page in top-level Admin Bar and Site Name submenu.

add-plugin-link-to-admin-bar.php

<?php
/*
Plugin Name: Add the plugin link!
Plugin URI: https://katz.co
Description: Add the plugin link to the Admin Bar
Author: Katz Web Services, Inc.
Author URI: http://www.katzwebservices.com
Version: 1.0
*/

add_action( 'wp_before_admin_bar_render', 'kws_add_plugin_menu_link' );

/**
 * Add the Plugins link for goodness sake!
 */
function kws_add_plugin_menu_link() {
	global $wp_admin_bar;

	//Add a link called 'Plugins' in the top-level menu
	$wp_admin_bar->add_node(array(
		'id'    => 'kws-plugins',
		'title' => __('Plugins'),
		'href'  => admin_url('plugins.php')
	));

	// And have the same link available in the submenu of the site name
	$wp_admin_bar->add_menu( array(
		'id'    => 'kws-plugins-sub',
		'title' => 'Plugins',
		'href'  => admin_url('plugins.php'),
		'parent'=>'site-name'
	));

}

I just slap this bad-boy in the mu-plugins folder.