iNotepad - Write and organize all your texts and notes on Mac.
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.
HTML-Notepad - HTML WYSIWYG editor for structured documents
Oxygen XML Editor - Oxygen XML Editor provides a comprehensive suite of XML authoring and development tools.
Notepadqq - Notepadqq is a linux clone (identical application) of Notepad++
Liquid Studio - XML Tools Provider: XML Studio - Graphical XML Schema Editor.