Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
NetTime - nettime is a time & attendance software solution.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
AboutTime - AboutTime is a superior source of time for your computer.
wnr - Better than pomodoro, this timer app balances work and rest.
Dimension 4 - The fastest and easiest way to synchronize your Windows clock.