I see. I don't know of any other list but I don't think you should assume that all alerts visible in the dashboard are sent over webhooks at this point in time. Just like with the dashboard api it's likely that not all alerts are added yet. The webhooks were only added in october last year...
Tbh, I'd focus on handling the ones in that documentation and perhaps start building a log of events that aren't recognized, you could even let the application notify you in those cases.
Keep in mind that the network wide section actually has a "settings changed" event too, so the one in the postman collection is likely that one rather than the systems manager one.