personal-management-system by Volmarg

Symfony bundle that will allow you to schedule all your commands just like unix crontab, with a nice admin panel. Maintained by j-guyon on GitHub, where it has earned 330 stars from the community.

Main OroCRM package with core functionality. Maintained by oroinc on GitHub, where it has earned 680 stars from the community.

Inshop CRM / ERP API. It's powerful framework allows to build systems for business with different workflows. It has on board multi language support, clients management, projects & tasks, documents, simple accounting, inventory management, orders & invoice management, possibilities to integrate with third party software, REST API, and many other features. Maintained by inshop on GitHub, where it has earned 258 stars from the community.