DocBook - DocBook is a schema (available in several languages including RELAX NG, SGML and XML DTDs, and W3C...
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Groff - The groff (GNU troff) software is a typesetting package which reads plain text mixed with...
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
pandoc - Pandoc is a Haskell library for converting from one markup format to another, and a command-line...
Slack - A messaging app for teams who see through the Earth!