Bugify - Bugify is a simple PHP issue tracker, designed to offer powerful bug tracking capabilities in an easy to use system.
16bugs - 16bugs is an all-in-one bug tracking software that makes it easier for you to manage all sorts of bugs in performance with the simple interface; ultimately, you will be more productive for sure.
Traq - Traq is a PHP powered project manager and issue tracker featuring multiple projects, milestones...
Pivotal Tracker - Pivotal Tracker: The awesome, lightweight, agile project management tool for software teams. Get your 30-day Free Trial started today!
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.
asitrack – Assisted Issue Tracking - Assisted Issue Tracking is an inclusive bug and issue tracking software that comes with a lot of customization and provides you with a simple way to add custom fields and dropdowns.