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.
Visual Studio Team Services - Visual Studio Team Services (VSTS) provides unlimited Git hosting, cloud build for CI, agile planning and continuous delivery.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
SourceTree - Mac and Windows client for Mercurial and Git.
Slack - A messaging app for teams who see through the Earth!
PractiTest - PractiTest is a cloud based Innovative test management tool.