Saw a guy sitting in one at the airport in Tallinn, Estonia. Wondered whether he’d oversleep his flight. It was right by our gate and he looked passed out.
I absolutely love homes with garbage disposals. Out of the many, many sits I’ve done over the past few years, only 3 have had them. They’re rare in my part of the USA for some reason.
Ah, yes, I’d forgotten the Echo Dot I had to buy for OH after a sit 
Not a HO/sit, but a summer sublet—a steam mop! Cleans floors like they’re brand new!
Not exactly a fancy gadget but bluetooth radios - older HOs tend to have one or more dotted around. Nice to listen to something that doesn’t involve an app and helps cut down on my screentime 
Not exactly a gadget but one HO put all their spice jars in a kitchen drawer with the labels facing up. I find that much better in my kitchen than having them upright in a cupboard (there’s not enough wall space to have racks for them). Discovered my first air fryer in a sit too. Oh, and a hoover that also washes the carpet, genius.
Some areas don’t allow garbage disposals. We lived in an area for twenty years where they were banned.
Maybe because we were in the country with a septic tank.
Their car! It even has decent gas mileage on it (current sit).
A Bosch cordless hoover with lights! Way better at picking up animal hairs than any of the others we’ve used.