Task Coach
Todoist
Remember The Milk
EssentialPIM
Todo.txt
Things
TickTick
Google Tasks
kdiff3
Beyond Compare
WinMerge
Meld
Araxis Merge
DiffMerge
P4Merge
Devart Code Compare
Task Coach
kdiff3Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Beyond Compare - Beyond Compare allows you to compare files and folders.
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.