Taskade - Make lists, organize your thoughts, and be inspired to get things done. Taskade is a collaborative space for your tasks.
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.
ToDoBot - Slack-native todos right in your Home Tab
Meekan - Connecting the world's calendars
Done? - A TODO list for productivity and procrastination lovers
Sidequest for Slack - Create and track personal or support team tasks, 100% inside Slack.