Plan - Plan is a better way to organize.
Superpowered - Power through the day without your calendar
Outplanr - Turn your to-do list into a real work plan
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.
Clean Google Calendar - Makes Google Calendar look nicer & launches as a desktop app
InstaCal - The missing menu bar calendar for MacOS