Clocks - A minimal world clock app for your Mac's menubar
Clocker - Keep track of people in different time zones
Klok - Keep track of anything with Klok's simple work timer and visual display of how your days...
144blocks - Colorful way to track your time! Inspired by Wait But Why
Dato - Better menu bar clock with calendar and time zones
World Clock iOS 8 Widget - Check the time, anytime. Just pull down Notification Center.