I've got a few things that come to mind:
Hue lights: The Hue lights in the master bedroom turn on at 9PM, since it's visible from the living room it's kind of a "Hey, you should think about going to bed soon" reminder. They turn off at 11PM as a "If you're still up reading you should probably stop" reminder. This is easy to set up with the Hue app.
More Hue lights: The Hue lights outside turn on a half-hour before dusk and off a half-hour after dawn. This needed to be set up by hand[0], but it's very much a set it and forget it type of thing. Once set up it automatically adjusts to the changing sunrise/sunset times.
Home security: I've got a bunch of cheap wifi cameras and Zoneminder keeping watch on my house. There isn't much automation happening here, but it solves a few problems for me.
Cat feeding: The vet was concerned that one of my cats was losing weight, so I set up a camera on the food dishes. Since the camera is hooked into Zoneminder, I can set it up to only record when there's motion. It's very easy see who comes to eat, how often they come, which food they eat, and roughly how much. This has helped in getting the portion sizes adjusted so that the cats are all happy and healthy.
Document Management: While not fully automated, I've found that putting documents into Mayan EDMS[1] instead of paper files has saved me a LOT of time when I need to find things. There is also huge potential for more automation by extending Mayan to do things with new documents based on their OCR'd contents.
I'm sure I've got others, but these are definitely the big ones for me.
[0] https://stackoverflow.com/questions/26782957/how-to-use-suns...
[1] https://mayan-edms.org/