XML Copy Editor - XML Copy Editor is a fast, free, validating XML editor.
Wondershare PDFelement - All-in-one PDF editor
Oxygen XML Editor - Oxygen XML Editor provides a comprehensive suite of XML authoring and development tools.
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Liquid Studio - XML Tools Provider: XML Studio - Graphical XML Schema Editor.
Foxit PhantomPDF - Edit PDF files with our feature-rich PDF Editor. Download Foxit PDF Editor to convert, sign, scan / OCR & more. A speedy PDF Editor alternative to Adobe Acrobat.