Dr.Explain - Dr.Explain software is a help file authoring tool.
JustNotepad.com - A free online notepad allows you to create any text or notes in your web browser.
Document360 - Self-service knowledge base software focused on SaaS Products & Enterprise Software Projects.
TakeNote - A web-based note-taking app with GitHub sync and Markdown support.
WinCHM - Creating CHM file, Make CHM file, Web Help. WinCHM Pro - Help authoring software (CHM, WebHelp, DOC, PDF) . With this powerful tool you can not only create chm file from scratch, but also convert a set of existing HTML files to a chm file.
PlicPad - Shareable notepad without urls