SugarCRM is the market-leading, commercial open source customer relationship management (CRM) application. SugarCRM's open source architecture easily adapts to any business environment by offering a more flexible, cost-effective alternative than proprietary applications.

Mantis is a web-based bug tracking system that has a suite of advanced features including: time tracking, wiki integration, email notifications, RSS, a RESTful interface, Twitter integration, roadmap functionality and preset workflows.

Redmine is a project management and issue tracking system for software developers. Redmine provides many of the features in Trac plus support for multiple projects, role based access control, time tracking functionality, Gantt charts, a calendar view and user self-registration support.

vTiger is an open source, web-based customer relationship management (CRM) system that competes with applications like Goldmine, SugarCRM and Salesforce.com. For companies with multiple employees and multiple customers, a rock-solid customer relationship management system is the cornerstone of the business.

Trac is an advanced tool for tracking software development projects. It provides a simple wiki, issue tracking system and tight integration with the Subversion revision control system.

OTRS is an Open source Ticket Request System (also well known as trouble ticket system) with many features to manage customer telephone calls and e-mails. The system is built to allow your support, sales, pre-sales, billing, internal IT, helpdesk, etc. department to react quickly to inbound inquiries.

Bugzilla is a web-based bug tracking system that allow individual or groups of developers to keep track of outstanding bugs in their product. Bugzilla competes with many commercial bug tracking systems and has many features its expensive counterparts lack.