GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.
Docusaurus - Easy to maintain open source documentation websites
Archivy - A self-hosted knowledge repository that allows you to safely preserve useful content that contributes to your own personal, searchable and extensible wiki.
MkDocs - Project documentation with Markdown.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.
Hyperbook - Hyperbook is a quick and easy way to build interactive workbooks, that support modern standards and runs superfast.