BuddyPress - WordPress social networking in a box.
eXo Platform - Digital workplace solution
Ultimate Member - The easiest way to create powerful online communities and beautiful user profiles with WordPress.
Basecamp - A simple and elegant project management system.
MemberPress - Easy to use WordPress Membership Plugin. Powerful Membership Software seamlessly integrates with WordPress, Stripe, PayPal and Authorize.net.
Slack - A messaging app for teams who see through the Earth!