Alternativ till imarvel för Slack med gratis licens

• Slack
  Alla plattformar Windows Mac Linux Chrome OS Android iPhone Windows Phone iPad Android Tablet Kindle Fire Windows S Web Self-Hosted Firefox Opera Safari Internet Explorer Vivaldi Browser Chromecast BSD Windows Mobile Wordpress Slack Electron / Atom Shell Chrome Microsoft Edge Gmail Twitter Yandex.Browser Google Drive Dropbox Brave Google Apps Trello Instagram GitHub Pages ASP.NET MVC Microsoft OneDrive DuckDuckGo
• Gratis licens
  Eventuell licens Gratis licens Open Source-licens Kommersiell licens