Bitrix24 - Bitrix24 is a free (for small businesses) social enterprise platform. It is a united work space which handles the many aspects of daily operations and tasks. Create your own social intranet in minutes!
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
LinkedIn Premium - LinkedIn is a social network helping brands and professionals to connect, identify sales prospects, hire talent, and promote their business.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Salesforce Chatter - Salesforce Chatter provides a suite of collaboration features to any application built on Force.com.
Slack - A messaging app for teams who see through the Earth!