YouTrack - Free, online, easy-to-use, fully customizable issue tracking and agile project management tool your development team will love, by JetBrains. Our cloud or your server.
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.
Pivotal Tracker - Pivotal Tracker: The awesome, lightweight, agile project management tool for software teams. Get your 30-day Free Trial started today!
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Redmine - Flexible project management web application
Trac - Trac is a project management and bug/issue tracking system. Provides an interface to Subversion and an integrated wiki.