MainWP is a suite of open-source self-hosted plugins & extensions for users who has multiple WordPress sites and want to control them from one central location. This includes sites on different hosts or servers.
WPMU DEV - Your All-in-One WordPress Platform. Build A Better WordPress Business. The hosting, tools, plugins, and support you need to run your WP business - all in one place.
WP Remote provides a single place to monitor and update all of your WordPress sites. It can handle updates to installed plugins and themes remotely via the WP Remote website, and also provides quick access to core updates.