I've used Moonlight (app) and Steam Link (both the app and discontinued physical hardware). They're both pretty decent, but I haven't used either in ages.
It depends on what you're trying to run, but both are free so you should just give it a try.
Edit: I misread the original post as being some silly question. I used to use the physical Steam Link for watching videos a long time ago, but if you're just running video files I'd recommend something like Plex.
This cover kinda slaps