1)   StorYBook 1.1
StorYBook is a free, summary-based open source software for creative writers like novelists and authors that helps to keep the overview over the strands while writing a book, a novel or a story. StorYBook assists you to structure your book.

 2)   Liquid Story Binder 7.81
Liquid Story Binder is a program designed for writers, novelists, and poets. It allows you to view your documents easily. It gives you the freedom to create while protecting your work. It is more than just your typical word processor.

 3)   PageFour 1.42
PageFour is a word processing package designed for writers. Its unique feature set combines a fully featured word processor with a powerful outliner - ideal for structuring your novel, fanfiction, blog, journal, or diary.