I started using Home Assistant on Umbrel about 3 months ago. I bought a bunch of wiz smart light bulbs from Costco for about 5 bucks a piece. So far:
I change the color of the lights in my office and the living room to remind me to change the cat litter.
The TV in my bedroom turns off at 11 pm every night.
The Roomba turns off when I turn on the TV in my living room because my wife doesn't like the noise while she's watcvhing TV.
I got a sonar device too, but haven't set it up yet.
I want to get a water sensor that turns all the lights in the house blue and automatically shuts off the water if a sink starts to leak.