Simple Outliner!

Todoist is a task manager thats useful, fast and easy to use.

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.

An easy to use, web-based to-do list. Get organized, stay motivated, and be more productive.

Task Coach is a well-structured, portable, open source todo / task manager (supporting 50 languages). It grew out of frustration that well-known task managers, such as those provided with Outlook or Lotus Notes, do not provide facilities for composite tasks. Over time, Task Coach has added effort tracking, budgeting, notes, priority adjusting, reminders, and many other features.

Moo.do is designed to be the best and easiest way to keep your life and thoughts organized: projects, to-do lists, appointments, contacts, reminders, events, and anything else you want to write down. As all modern apps should be, Moo.do is available on any computer, tablet, or phone and synchronizes all devices and users in realtime.

germ.io is a project management tool that is centered around ideas and taking them through to execution.

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

To Round advantages Focus only on relevant tasks Empty your mind in less than two taps Visualize your priorities

GoodTask 3 is a Powerful Task/Project Manager based on iOS Reminders & Calendars. You can use it as simple checklist to focus or as complex project management tool to get big things done.

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.

Timeline is your personal task assistant.

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.