Dr.Explain - Dr.Explain software is a help file authoring tool.
Greenboard - Generate beautiful static api documentation
MadCap Flare - Documentation for Any Audience, Language or Format
ThinkJS - use full ES6/7 features to develop web applications
HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.
snazzyDocs - Publish and Host your documentation in seconds!