Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Online Stopwatch and Timers - Sometimes everybody need to count time for some reason.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
wnr - Better than pomodoro, this timer app balances work and rest.
Meinberg NTP - NTP client and server download for different operating systems.
Gestimer - For those little reminders during the day