Effortless is a Mac app that helps you stay focused and do one thing at a time.
Really enjoy the implementation of this simple app. Would be useful to consider any of the following in a Pro plan:
1 - Pomodoro
2 - Integration with Asana/Todoist/Trello/etc
3 - Statistics
Super-simple interface and the notification alarms that your time is running out
Cannot configure it with custom goals...yet?