Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Free Countdown Timer - Free Countdown Timer is a free, full-featured and user-friendly countdown timer for Windows
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
wnr - Better than pomodoro, this timer app balances work and rest.
CountDown Kings Free Countdown Timer - CountDown Kings Free Countdown Timer is a free countdown timer for Mac OS X and Windows operating systems.
LClock - Longhorn systray clock program