The Tweet Hereafter - The last tweets of the deceased

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

Scavenger - An augmented reality scavenger hunt for cash prizes

GoodTask - Task manager based on iOS reminders and calendars

WeCroak - An app to remind you of death

Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.