Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
XNote Stopwatch - Try the most feature-rich stopwatch and timer software on the net for free!
wnr - Better than pomodoro, this timer app balances work and rest.
Free Countdown Timer - Free Countdown Timer is a free, full-featured and user-friendly countdown timer for Windows
Gestimer - For those little reminders during the day
CountDown Kings Free Countdown Timer - CountDown Kings Free Countdown Timer is a free countdown timer for Mac OS X and Windows operating systems.