Aika - A simple alternative to Google Calendar for timeblocking/timeboxing.
Tomato Timer - TomatoTimer is a flexible and easy to use online Pomodoro Technique Timer
Zonebox - Get more done by timeboxing your tasks
YAPA - Pomodoro timer
Is Invisible - Hard to find, beautifully designed products
focus booster - focus booster is a simple timer application following the 'Pomodoro technique' for time...