WinCHM is recommended for small to medium-sized businesses, educators, and individual users who need to create help documentation without a steep learning curve. It's particularly suitable for those who require a straightforward tool to produce professional-looking help files without having extensive technical skills.
HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.
Kchmviewer - Kchmviewer is a free, open-source CHM (MS HTML help) and EPUB viewer for Unix, Mac and Windows...
Dr.Explain - Dr.Explain software is a help file authoring tool.
CHM Editor - Best solution to edit CHM files
ExtraCHM - A fully featured reader for Compiled HTML (chm) documents.
Read CHM - Read CHM is ultimate CHM (Compiled HTML Help) file reader.