Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Timer Tab - Online countdown timer, alarm clock, and stopwatch.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
Gestimer - For those little reminders during the day
wnr - Better than pomodoro, this timer app balances work and rest.
Online Stopwatch - Online Stopwatch is free to use online tool that allows you to keep track of the important events and tasks that you are performing.