KanbanFlow - KanbanFlow is a Lean project management tool allowing real-time collaboration between team members. Supports the Pomodoro technique for time tracking.
GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
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.
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Kantree - Kantree is an adaptable and intuitive project manager for the enterprise.
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.