Camunda - The Universal Process Orchestrator
MySQL - The world's most popular open source database
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.
Datahike - A durable datalog database adaptable for distribution.
jBPM - jBPM is a flexible Business Process Management (BPM) Suite.
MarkLogic Server - MarkLogic Server is a multi-model database that has both NoSQL and trusted enterprise data management capabilities.