Camunda - The Universal Process Orchestrator
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
jBPM - jBPM is a flexible Business Process Management (BPM) Suite.
UML Designer - UML Designer provides a set of common diagrams to work with UML 2.5 models.
ProcessMaker - ProcessMaker is an easy to use BPM and workflow software solution. It is used to design, automate, and deploy business processes of any kind.
ARIS Express - ARIS Express is based on the proven ARIS methodology and industry standards.