1. TiddlyWiki โ€” a non-linear personal web notebook

  2. Org: an Emacs Mode for Notes, Planning, and Authoring

  3. 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.

    freemium $12.5 / Monthly (Per user - Business Class)

  4. Todoist is a to-do list that helps you get organized, at work and in life.

  5. Milanote is a note taking app for creative work.

  6. Laverna is a JavaScript note taking application with Markdown editor and encryption support.

  7. DEVONtechnologies develops DEVONthink, DEVONagent, and other Mac and iOS apps for document and information management and web research.

  8. Windows desktop application to stay on top of your daily tasks.

  9. Paperwork is an open source note-taking & archiving app written in PHP.

  10. to-do list app that integrates with Gmail and Google Calendar

  11. The note-taking app with robust Markdown editor, supporting macOS, Windows, and Linux.

  12. A fork of the original Notational Velocity with some additional features and interface modifications