Apps to Outline mode

Liquid Story Binder XE is a comprehensive word processor and writing environment designed specifically for authors working on long-form projects like novels. It integrates outlining, scene management, character tracking, and various planning tools to help writers organize their creative process.

yWriter is a free word processor designed specifically for novelists. It breaks down your manuscript into manageable chapters and scenes, providing tools for tracking characters, locations, items, and plot points, allowing you to focus on the creative process.

Org-mode is a powerful and flexible mode for GNU Emacs, designed for note-taking, project planning, to-do list management, and authoring documents. It utilizes simple plain text files with intuitive markup.