Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Hidden Bar - A ultra-light MacOS utility that helps hide menu bar icons.
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
Bartender Mac App - Bartender is an award-winning app for macOS that superpowers your menu bar, giving you total control over your menu bar items, what's displayed, and when, with menu bar items only showing when you need them.
Things - Things is an easy to use task manager.
Vanilla - Vanilla is a free Mac app that lets you hide icons from your menu bar.