GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.
Papermind - Papermind Slack App is a collaborative article-editing and document management platform for Slack
MkDocs - Project documentation with Markdown.
Slenke - Project management & team collaboration
Docusaurus - Easy to maintain open source documentation websites
Trainual + Slack Integration - Capture knowledge or access training right inside Slack