Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
Online Alarm Kur - Free online alarm clock, set alarm easily on your computer using the internet alarm clock without downloading any software, wake up in time with the loud online alarm clock.
wnr - Better than pomodoro, this timer app balances work and rest.
TIMEBOX - An advanced timer for professional meeting facilitators
Date Reminder - Date Reminder reminds you of recurring or nonrecurring events, like birthdays, bills to pay...
Stopwatch is best for manage time.
I recommend - Online Stopwatch and Timers.