Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
StatusOk (Open source) - Get notified through Slack/email when your website is down
Todo - Todo is a to-do and task list app.
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
Prodeus - Track your time learning on YouTube to earn your free degree
Get Notified - Get Notified when something happens