I am curious whether there's a more capable system cron that supports that kind of thing. Quartz job scheduler (java), AWS, and CF obviously wouldn't qualify. I think this is only possible if you're using a heavyweight job scheduler like those. Or... systemd.

It ultimately doesn't matter "for real", because almost nobody without some horrific legacy system to integrate with would need to use anything more than lists, ranges, and increments. There's a reason nobody's added these features to system crons. Clever trigger times for events that don't really need to be triggered at clever times... sure, but lacking that capability wouldn't change anything, the trigger would just be a more boring one.

Events like "last Friday of the month" or "nearest weekday to the 1st of the month" or even "Friday the 13th" are more for business logic, not system crontabs.