Slack - A messaging app for teams who see through the Earth!
Confluence - Confluence is content collaboration software that changes how modern teams work
MS SharePoint - Share, organize, and discover information with Microsoft SharePoint. Learn about SharePoint Online, OneDrive for Business, and Apps for SharePoint
Flock - A faster way for your team to communicate
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Mattermost - Mattermost is an open source alternative to Slack.