Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Google Calendar - Spend less time managing your day & more time enjoying it
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.
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.