Custom MacOS notifications

yo notifier - I use this, works pretty well. compile with xcode if you want to do your own branding
terminal-notifier - another popular option

I've used Yo in the past also and it works well. I may have some old scripts around that were designed to send a custom message, icons and so on to Yo and have it display a notification.

Keep in mind that under 10.15 now, your message may not automatically pop up without the user approving it, as per this thread. You could always create a profile using some of the methods on that thread to pre-approve it, at least until Jamf fully bakes that profile payload into the product.

If you're running things in a script, you can call the Apple notifications with the code below:

osascript -e 'display notification "Installing Microsoft Silverlight" with title "DEP - Configuration"'

I use this to display notifications to our technicians when our app installation script is running.

You should be able to create a policy with out any payloads...

1. Set the trigger to re-occurring check in
2. Frequency can be ongoing (which will continuously pop up each check in) OR once per computer
3. Then in the policy, select the "User Interaction" tab
4. fill out your start message (kind of like the subject line in an email)
5. Complete Message (fill out what the message is)

Then scope it to your machines... which the message will pop up as a 'Management Action' notification at the top right corner of your client machines.

Hope this helps!