Gone - An ephemeral to-do list
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Streaks - The to-do list that helps you form good habits.
Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Pomodone - Pomodone is the easiest way to track your workflow using Pomodoro technique, on top of your current task management service.