Ollert - Learn what your Trello boards aren't telling you
7todos - A task board for indie hackers
Vacation Tracker - The easiest way to track your team’s vacations and days off.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Punchtime - Nifty time tracking for Trello users and teams
Tasks - The new task app from the team that brought us Wunderlist, Microsoft To-Do is a great way to manage tasks. List everything you need to do—or import tasks from Outlook, Todoist, and Wunderlist so you don't have to start over.