Just wanted to update there is now a Clock App that integrates directly into Zoom: Timer - Clock, Agenda, Countdown & Stopwatch
Once you’ve installed it, click “Apps” in the bottom bar of any Zoom meeting and select the Timer App. In the top left of the App you can select between Clocks or Timers.
As much as this is a good app, it’s ridiculous to pay to only have a clock feature on Zoom.
It’s just a clock that shows the time of day is what people are asking for.
Just wanted to provide a 2024 update that the Timer - Clock, Agenda, Countdown & Stopwatch integrates directly into the Zoom application and can display a Clock, as well as Timers & Agendas.
It now has many customization options including the way the Timer appears in Zoom, optional audio alerts, and timer cycling. The basic version is free (and there are paid options for all the bells and whistles).
Thanks. This is helpful I tried this, although in order for other participants to see it it needed to be downloaded by them and those using mobile are not able to use it.
Thanks @jowzien31 . Re BlueSky Timer App : if you select the “My Video” display method you can share a timer or clock visible to all participants and they don’t need to download or install the app (and it works on mobile too)! Some more details on the display options here. 
