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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.

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.

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.

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.

Buckets is a simple & intuitive task organization, cloud-based app that allows professionals & non-professionals alike to collaborate

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

Zenkit is a collaborative SaaS platform for project management, database building and more. Follow your data through its entire lifecycle, from fluid brainstorming and research through to a structured system for collaborative use. Zenkit is the flexible workspace you can use to organize anything.

Stacks is an easy to use task manager that helps to organize your tasks in an elegant and intuitive way. Using kanban paradigm for managing your projects Stacks offers a flexible and visual way to organize your tasks with ease. Combining powerful features like tags, task grouping, quick search and attachments with a beautiful user interface, Stacks aims to make task management both easy and fun.

Taskade is a simple to-do list and task manager. You can instantly make a list and share it with your friends, family, and colleagues. Use Taskade to capture your ideas, goals, and daily tasks.