I’ve got a few fun ones:

At night, my cat sometimes gets the zoomies, so I have a projector pointed at a wall with a motion sensor. When he goes on his tear through the house while we’re sleeping, the projector turns on and plays a video of strings moving on the wall. This tires him out without him screaming at us to play with him. It turns off again after a few minutes with no motion.

The lights and Roku screens in my office are on a motion sensor, but are also linked with a seat sensor so they don’t turn off when I’m at my desk. Sitting at the desk also sends a Wake on LAN packet to my computer. Sitting at my electronics workbench changes the lights to bright white with another seat sensor.

Lights (HA), desktop wallpaper (with Wallpaper Engine), and in-computer RGB (using OpenRGB) change from blue/pink during the day to dark red/orange at sunset so being in my office late doesn’t mess with my sleep.

A macro button next to my keyboard disables my screens and turns on a fan pointed at my VR area for workouts.

For me one of my favourites are my extractor fan control in my bathrooms. I have a switch on the fan and a humidity sensor close by. Turn on the shower and the extractor will turn on until the humidity is lowered enough, then switch off. In addition I have a static programmable button to press should you need it for other reasons. I just love the world of entities and how they link together to make something functional.

The ones I use the most are:

• Turning on lights and setting specific scenes when I turn on TVs in my bedroom, living room and theater room.
• Brighten lights whenever Plex is paused or finishes playing, which is great in a dedicated home theater where the lighting is very dark when watching a movie. This has actually helped improve many hang out nights with friends because the moment after a movie finishes is less awkward, leading more naturally into a nice conversation before every heads home.
• Reminder notifications for when washing machine or dryer cycles finish, or when my garage door has been open for more than 15 minutes (unless I override that with a toggle on my dashboard).
• Turning off all of my lights and switches when I leave the house, unless a boolean variable is flipped (e.g. if someone else is at my house w/o me, which is unusual since I live alone). Well, not quite everything, there are a few devices like a couple power monitoring smart pugs that always remain on.

Which addon did you use for the paperless-ngx integration?

I don’t have a lot of automations yet, but a really useful one has been using smart plugs to detect when the laundry machines are running so that Home Assistant can send alerts when they finish.