Steam Link App is now available on RaspberryPi 3B a 3B+, popular single-board computers.
Fot the installation, you need to use only two commads for Raspbian Stretch. Steam Link is implemented in RetroPie and ETA PRIME.

What is Steam Link App? The the service which streams games from your computer directly to your device (mobile, RaspberryPi).
So you can play all games which your computer supports.

Installation on Raspbian Stretch

curl -#Of
sudo dpkg -i steamlink_1.0.5_armhf.deb

Originaly shared:

Link to blog