Things - Things is an easy to use task manager.
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Llama Life - Say goodbye to never-ending lists, and hello to daily bliss
Meekan - Connecting the world's calendars
Everlist Task Manager - Groceries, trips, errands, and daily todos managed simply. get your tasks under lovely control.
Sidequest for Slack - Create and track personal or support team tasks, 100% inside Slack.