Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
7todos - A task board for indie hackers
Taskful - Deadlines, meet your match.
Butterfly - Butterfly is the web platform & chat-bots that offer real-time coaching to continuously develop managers based on their team's feedback.
Taskade - Make lists, organize your thoughts, and be inspired to get things done. Taskade is a collaborative space for your tasks.
Slash - A "productivity machine" that forces you to do tasks 1-by-1