The Unarchiver - Get the top application for archives on Mac. It's a RAR extractor, it allows you to unzip files, and works with dozens of other formats.
CHM Editor - Best solution to edit CHM files
zpaq - Incremental Journaling Backup Utility and Archiver
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.
FreeArc - FreeArc is a free and open source file archiver developed by Bulat Ziganshin.
Microsoft HTML Help - Microsoft HTML Help is the standard help system for the Windows platform.