OmniOutliner is a start-to-finish writing app. Perfect for collecting information, outlining Big Ideas, adding structure to any sort of writing, and much more. From grocery lists to email drafts to long-form composition.
Dashword is by far the most convenient and user-friendly tool for creating any semantic network, be it your business idea, an abstract of a lecture on computer science, a script for a movie or a recipe for your favorite dish.
Visual Outliner is an outliner software for Windows, and it uses OPML as native file format. It's not just another tasklist application, but a real outliner editor that can be used to write, view, modify, and maintain hierarchically arranged text.
Zavala is a modern take on a traditional outliner. It supports all the things you want in a Mac app like multiple windows, keyboard shortcuts, a customizable toolbar, and a full menu bar.