Dato - Better menu bar clock with calendar and time zones
Clocks - A minimal world clock app for your Mac's menubar
Clocker - Keep track of people in different time zones
Superpowered - Power through the day without your calendar
Every Time Zone - Online tool for keeping up with times around the world.
Itsycal - Itsycal for Mac. Itsycal is a tiny menu bar calendar. If you want, it will display your events as a companion to the Mac Calendar app. You can also create and delete (but not edit) events. Download Itsycal for macOS 10.