MeetingBar is described as 'Your meetings before your eyes! MeetingBar shows your calendar events in the status bar. Create and join meetings in one click. Powerful' and is a Calendar App in the Office & Productivity category. There are more than 10 alternatives to MeetingBar for Mac, iPhone, iPad, Apple Watch and Online / Web-based. The best alternative is Itsycal, which is both free and Open Source. Other great apps like MeetingBar are Fantastical (Paid), BusyCal (Paid), Dato (Paid) and KRON (Paid).
Itsycal is a tiny menu bar calendar. If you want, it will display your events as a companion to the Mac Calendar app. Itsycal has Dark Mode, ISO week numbers, a customizable system clock replacement, and more.
Fantastical is a flexible calendar with natural language event creation, a beautiful calendar and event list, support for CalDAV (including Google Calendar delegates) automatic alarms, and instant searching.
Dato is a replacement for the system menu bar clock. By default, it looks exactly the same, but when you click it, you get a small calendar, calendar events, the current time in various time zones, and more.
How Long Left is a simple menu bar app that displays the time left of your current calendar event in the menu bar. Use it during a meeting, at work, or in class when you want to know how long you have left.
Up Next See your day at a glance. Integrated with Google Meet so you can quickly join meetings with command-J or present to meetings with shift-command-J. Up Next is a menu bar app for macOS 10.12+. Install the latest version from the App Store. ??
Meeter simplifies your workflow for joining and issuing calls. Simply connect your calendar on your Mac and you'll be able to easily join any scheduled call from your calendar (currently supported are Zoom, Hangouts, Webex, MS Teams and Google Meet calls).