Recounting in my head and there are 8 pulleys total; crank, AC, PS, tensioner, water pump, sheave, idler, alt.
The sheave pulley which, the clutch fan is attached to can go bad. The bearings wear out.
You can use a long screwdriver instead of a stethescope to pinpoint the noise too.
92 Volvo 740 Wagon aka "Mutt mover"