For all AMPs, I suggest having at least 1 disk usage alert:
Disk Usage. Partition Percent Used >=75%
For closed environments with repeat users:
New Client. Choose wired/wireless mode. Folder set to Top, and All Groups.
This will let you know if any new users are seen in your environment. Noise only comes if clients get new devices, but otherwise, you'd expect no activity unless a new hire comes in. Less useful if you allow many guests onsite.
If you're really good at keeping up with your Actual vs Desired config updates:
Config Mismatch
This alerts you when a device audit returns a mismatch.
If you're feeling like your network is pretty loaded and may need a refresh:
Device Resources. Device Type = Controller, % CPU Usage >= 70% for Duration 15 mins.