Couple of missing items here, mostly regarding UNSHROUDED rotors.
A common propeller must meet an overspeed test demonstration, 141% of takeoff RPM IIRC. If a blade separates above that speed, it's in the "extremely unlikely" category, thus beyond certification intent. However experience shows that in a worst-case situation, it can happen.
I'm sure the GE36 and the like had to meet such an overspeed test if it were to be certified.
What do propellers have to do with this discussion
What does overspeed have to do with this discussion
What's a GE36?