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.
Redmine - Flexible project management web application
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Trac - Trac is a project management and bug/issue tracking system. Provides an interface to Subversion and an integrated wiki.
OpenProject - OpenProject is an open-source project management software with a wide set of features and plugins.
Basecamp - A simple and elegant project management system.