KanbanFlow - KanbanFlow is a Lean project management tool allowing real-time collaboration between team members. Supports the Pomodoro technique for time tracking.
Jira - The #1 software development tool used by agile teams. Jira Software is built for every member of your software team to plan, track, and release great software.
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.
Redmine - Flexible project management web application
Kantree - Kantree is an adaptable and intuitive project manager for the enterprise.
Mantis Bug Tracker - Mantis Bug Tracker is a free and open source, web-based bug tracking system.