If you have a shared Reminders list, Fantastical for Mac will notify you if someone else updates it. I don’t need to see these notifications, but it took me a little while to discover how to mute alerts for specific Reminders lists.
It’s not, as one might suspect, unders Preferences > Alerts. You actually mute the alerts under Preferences > Calendars, and it’s not at all obvious that this is where you do it.
First, open Preferences (Fantastical > Preferences or ⌘,). Then go to Calendars and right-click the Reminders list that you want to mute. Select Get Info.
Check Ignore alerts and Ignore shared calendar notifications as shown in the screen shot below. Then click .
This method also works for muting alerts from individual calendars.