XML Copy Editor - XML Copy Editor is a fast, free, validating XML editor.
Zim Wiki - Zim is a graphical text editor used to maintain a collection of wiki pages. Each page can contain links to other pages, simple formatting and images.
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.
TiddlyWiki - a non-linear personal web notebook
footnote - A beautiful, fast, and simple note taking app in the style of elementary
Wiki on a Stick - Self-contained desktop wiki