Posts: 31,445
Joined: Jan 2011
Pretty much every network tuner ever made, like HDHomeRun Prime. This is what I personally use. I use mine with a paid cable subscription, but there are units for over-the-air TV signals, satellite, etc. It's not only legal, but I even get a discount on my bill for providing my own equipment.
Several TV providers in parts of the world provide 100% legal streams for their customers, rather than use cable boxes or some other TV box.
Some people even use it to monitor their intranetwork security camera streams.