Ben WP Monitor is a plugin I made to solve a common issue that I had at one of my jobs (and yes this is on the WordPress public repository). WPMonitor is the quick and easy way to manage multiple sites from the dashboard.
WP Monitor makes a dashboard widget that uses javascript libraries and color indicators, creates an at-a-glance health check for your site, telling you how many plugin updates, theme updates, core updates, PHP version, SSL, and lots of other key information for maintaining a WordPress website! The best part is that with a single click you can create a print out or pdf (for a paperless option) to get reports on all 20 of the sites you manage in 2 minutes.
The plugin is free and, as I said, solved a common issue I had at work. Never again spend your time looking for each vital statistic on your WordPress website for maintainance, just use WP Monitor to get the information quickly and easily.