Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Makerlog - Makerlog is the dead-simple task log that helps you stay productive and ship faster.
Taskful - Deadlines, meet your match.
WIP.co - Work in progress. We are a community of makers who help each other ship product.
Taskade - Make lists, organize your thoughts, and be inspired to get things done. Taskade is a collaborative space for your tasks.
Indie Hackers - Connect with fellow entrepreneurs, developers, and bootstrappers who are sharing the strategies and revenue numbers behind their companies.