Company Nasa Trained Monkeys created these great apps:
Pomodoro Timer: Focus on your productivity and beat procrastination using the Pomodoro Technique, Timers - The Multi Timer App, Pomodoro Timer: Focus on your productivity and beat procrastination using the Pomodoro Technique, Square Runner - The Game, Take a Break - Stress-Free Productivity, Take A Break - Stress-Free Productivity, Thyme - Quick Timers, Interval Timer: Focus on your productivity and beat procrastination, and others..