Datahike - A durable datalog database adaptable for distribution.
Altova XMLSpy - The XMLSpy XML Editor is a powerful tool for editing XML and related technologies. It is the only XML Editor with patented SmartFix validation, enterprise-grade editors, converters, debuggers, and code generators.
PlanetScale - The last database you'll ever need. Go from idea to IPO.
Oxygen XML Editor - Oxygen XML Editor provides a comprehensive suite of XML authoring and development tools.
Datomic - The fully transactional, cloud-ready, distributed database
Liquid Studio - XML Tools Provider: XML Studio - Graphical XML Schema Editor.