DIRECTV recently published a new list of DIRECTV 4K Ready TVs on their site. It's probably the simplest list I've seen, so I'm posting it here for you all to enjoy as well.
| Brand | Year | Models |
|---|---|---|
| Samsung | 2014 | All Smart UHD/4K TV Models |
| 2015 | JS9500, JS9100, JS9000, JS8600, JS8500, JS850D, JU7500, JU750D, JU7100, JU710D, JU6700, JU670D, JU6500, JU650D, JS8000, JS7000, JU6400, JU640D | |
| LG | 2015 | UF9500, UF7600, UF7690, UF7700, UF8500, UF8600, EG9600, EF9800 |
| Sony | 2015 | XBR-75X940C, XBR-65X930C, XBR-75X910C, XBR-65X900C, XBR-55X900C, XBR-75X850C, XBR-65X850C, XBR-55X850C, XBR-49X830C, XBR-43X830C, XBR-65X810C, XBR-55X810C, XBR-49X810C |
There's a more comprehensive list that is "usually" up to date, here.