I am in bed right now but tomorrow I can take a look at my setup and suggest some things.
A couple examples: I connected my litter robot (litter box) to HA and it notifies me when the cats break something, and I can see statistics of which cats use it and how often to keep an eye on their health. I have it turn on the portable air filter after a cat goes and leave it on for 15 minutes. I also automate 2 dehumidifiers based on humidity sensors I built with some tiny wifi microcontrollers and hard wired humidity sensing chips (I can tell you more about that with specific models later)
I also control a roomba-style lawnmower with HA.
Lots of other little things too like sunset-based light triggers and doorbell-triggered events and stuff.
All of these are things I already owned before I set up HA. Just browse through integrations and also get HACS (a community extension store built-in to the UI) and see what you already own that can be connected. I bet it will be more than you expect.