YouTube TV has yet to outline all the specific detail, but it did point out in the tweets that, with respect to Samsung, that the service is available on 2016 and 2017 models. According to YouTube TV’s device support page, 2016 and 2017 models from LG also support the service.
That page also notes that YouTube TV will becoming available on Sony Linux-based TVs.
After starting on smartphones, tablets and web browsers, YouTube TV recently adds apps for several TV-connected platforms, including certain Android TV devices, and Xbox One consoles. YouTube TV also supports TVs with Chromecast built-in.
YouTube TV also has work underway to launch apps for Apple TV (complementing support for AirPlay) and the Xbox One X.