Nest- fire alarm (amazing, pings your phone before the alarm goes off, tests itself whilst you're out,), thermostat (also amazing).
Gonna get a nest doorbell when we move.
We also have a couple WiFi plugs (living room and bedroom lamps), and a WiFi light bulb in the porch.
Chromecast on the telly is brilliant too, turning it off and on remotely, and shouting "hey Google play hey Duggee on Netflix" is the best thing ever when the toddler is pissing me off. When the tv is on but nothings playing it slideshows our favourite family photos.
We run everything through two Google mini's, one upstairs one downstairs.
We've set up a lot of functions on If This Then That too.
We've recently sold our house and we offered to revert smoke alarm and thermostat to standard but our buyer wanted to buy them 😂