Sure. I don’t have many enabled right now but some that I’ve used that are probably useful to others
I have a zigbee smart lock that was relatively cheap but didn’t have a sensor on it to detect if the door is open or closed, just a timer built in. To make the lock smarter so that it won’t attempt to lock if the door is open, I’ve used a $10 aqara sensors to detect if the door is opened or not and then combined those with the door lock to say, trigger a door lock after 5 minutes of the sensory closing, but only if the door isn’t opened again.
Another Aqara sensor automation that I don’t use any more as we moved to a house that has a carport rather than garage, but I used a contact sensor on my ‘dumb’ garage door to detect if the door was open or not. If the garage door was opened, the garage light would go on. Could do this other ways such as with motion sensors etc but unlike a motion sensor this would keep a light on until the door closed.
I have a robotic vacuum that I would automatically turn on when every person left the house. If someone was detected returning within a KM of the home, the robot would then return to the dock so it was out of the way when people got home. I really really loved this automation, but I haven’t used it since having kids 4 years ago as there has inevitably been too many toys etc that the vacuum would pick up now days. If your floor is relatively tidy but, it’s a great way to do a vacuum.
I haven’t explored it yet but Home Assistant pulls in my data from my solar panels and battery. In theory I could probably automate some of my appliances based on power generation or battery charge. Haven’t explored that fully yet however.
Those are some thoughts. Right now I use it mostly to bridge devices that otherwise don’t talk together or integrate with HomeKit. Haven’t played around with the automations for a bit, but meaning to go in and have a play with it more at some point. It’s a product I tinker with for a few weeks then let simmer for months before coming back too.