ERPNext - The ERP Software that helps you take full control of your business. ERPNext is both powerful and easy to use.
Odoo - An all-integrated business app suite to unleash your growth potential.
Dolibarr - Dolibarr ERP CRM is an Open Source software package for small, medium or large companies, freelancers or foundations to manage business. It's a PHP project built by modules addition (invoice, proposal, contact, stock, order, hr, agenda. .
inoERP - inoERP is an open source php based enterprise management system.
iDempiere - iDempiere Business Suite ERP/CRM/SCM done the community way.
Tryton - Tryton is a three-tiers high-level general purpose application platform under the license GPL-3 written in Python and using PostgreSQL as database engine.