Timer Tab - Online countdown timer, alarm clock, and stopwatch.
Amazing Marvin - Customizable personal productivity tool
Gestimer - For those little reminders during the day
MenuTimer - MenuTimer is a timer that you can use from your menu bar.
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.
Focusmate - Distraction-free productivity via virtual coworking