If you ever need to get a fast ethernet connection to somewhere that is difficult to run a cable to or is too far for your wireless router to reach, ethernet over power is an option for you.
The way it works is that you plug one adapter into a wall outlet and run a wired ethernet connection into it. Then plug a second (or as many as you want) into other power outlets around the house and you can plug your ethernet cables into them for a solid gigabit connection.
The adapters gigabit adapters I bought in 2019 areTP-Link AV1000
I then bought two more in 2023. The newer models actually allow the power plug to pass through so that you don’t lose a power plug.
Where I used these plugs was for getting ethernet out to where I have security cameras. The one to the garage was easy but the one to the shed was a little tricky.
What I learned is that the ethernet signal can not pass through a GFI breaker and since I have a GFI breaker for the power run out to shed.
The reason for this is that the way a GFI breaker works is that it has two coils of wire internally wrapped in opposite directions. The magnetic field for the current heading out is cancelled by the magnetic field for the current returning. If the current going out and in are not equal, then the magnetic fields don’t cancel and the breaker is tripped. This works great for not electrocuting yourself but does not work great if you are a data signal trying to get through that contraption.
The way I got around this was to install a new outlet inside the house between the breaker and the shed. I now have two adapters in my basement, one puts ethernet on the power lines inside the house and the second puts ethernet on the power line out to the shed.
The result is that I have gigabit internet to the camera in the garage and gigabit internet to the camera in the shed.