Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
TimeLeft - TimeLeft is a versatile desktop utility - it can be used as a countdown clock, reminder, clock...
vClock - Web based time tools including Alarms, Timers, Stopwatch, and World Clocks. vClock is customizable and has a clean user interface.
YAPA-2 - YAPA-2 is a minimalistic desktop timer app for Pomodoro Technique users.
wnr - Better than pomodoro, this timer app balances work and rest.
YAPA - Pomodoro timer