2002 toro garden tractor, 266h, died while mowing.wouldn't re-start. Battery good. Starter good. Ignition switch does nothing. 10 amp fuse blown. Replaced but no help. Think fuse is tied to the PTO system.

Well, the fuse should probably be 20amp

Only replace the fuse with what was OEM. Start tracing your power from the battery to the ignition, then to the solenoid and then starter. Somewhere along this path your power drops out. My money is on the switch.