Bugs, improvements, features and tasks are found in any software development. Managing them can be a hassle. This list will get started in the issue tracking landscape.
Add your suggestion Subscribe to this listOpen source, straightforward tool where the design is completely ignored. Does the job.
Very complete issue tracking and code integration to plan, collaborate, and ship products. Time management add-ons included and a lot of compatible Atlassian products.
Redmine can be used for total project management, but is ideal for issue tracking.
Slick tool for task management. Not designed as a issue tracker, but able to do the job. Specially for the smaller teams and tasks.