Orgzly!

Workflowy lets you organise your brain into easily manageable lists. It also works as a single-pane outliner with inline notes. It offers one-click hoisting (zooming into branches). The online version syncs with mobile apps.

A hierarchical note taking application, featuring rich text and syntax highlighting, storing data in a single xml or sqlite file.

Dynalist is the easiest way to be organized and stay on top of things.

Org-mode is for keeping notes, maintaining ToDo lists, doing project planning, and authoring with a fast and effective plain-text system.

Checkvist is a web tool for creating online outlines, hierarchical task lists, collecting and structuring all kinds of information. It has an outstanding keyboard support so you can easily re-structure your lists, filter, hoist and beef them up with tags, due dates, links, or attachments. Collaboration, Markdown, code highlighting, import and export (OPML, text) make Checkvist an ideal hub for working on complex IT projects.

MyLifeOrganized (MLO) is a personal task outliner and to-do list manager which will help you to organize your goals, projects and tasks into a tree.

UV Outliner is a small and powerful single-pane outliner. It is intended for creating, organizing, and collecting information.

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.

Tkoutline is a single pane, cross-platform outline editor written in Tcl/Tk . With this editor, information can be structured hierarchically in an outline and outlines can be hyperlinked together to create a web of outlines.

TreeLine just stores almost any kind of information. A tree structure makes it easy to keep things organized. And each node in the tree can contain several fields, forming a mini-database. The output format for each node can be defined, and the output can be shown on the screen, printed, or exported to html. TreeLine can also act as a basic editor for any kind of XML file.

Cross-platform app for Mac, iPhone, iPad, and iPod Touch. Sync outlines between computers and devices with iCloud. Sync outlines with Evernote, Import and export outlines in OPML format.

Create your lists, preserve your story, and stay inspired.

Outspline is a free and open-source modular outliner whose functionality can be extended with addons. The most important addon is Organism, which adds advanced time management features and turns the application into a personal organizer, perfectly suited for working with todo lists, scheduling tasks and reminding events.

Indispensable information organization tool for knowledge workers.