Steam Link
The Steam Link seems to be a small computer that you can hook up to your TV through HDMI. It has an Ethernet port so you can use Valve's in-home streaming without hiccups. There's also three USB ports to send input back to the PC you're streaming from. Steam Link will be available in November this year for $49.99.
Steam Machines
There will be a bunch of Steam Machines released in November by different manufacturers. Even though specifications and price points of the actual machines have probably changed significantly, we expect most of the manufacturers announced by Valve during CES 2014 to be part of this.
Steam Controller
The Steam Controller will be released in November this year as well. It's available separately for $49.99. International prices coming closer to release.
Source 2
Source 2 will be free to all content developers. There will also be Vulkan support in Source 2, we'll probably hear more about Vulkan (and Valve's involvement) in the upcoming GDC talk. Valve have not mentioned licensing/royalty costs yet.
VR
Valve have officially announced their "Lighthouse" room tracking system used with the HTC Vive through two base stations. Valve says Lighthouse can be integrated into a multitude of different hardware including televisions, mobile phones, headsets and input devices. Alan Yates's weird "Chief Pharologist" Twitter bio sure makes a lot of sense now.
Valve intends to make Lighthouse freely available to any hardware manufacturers interested in the technology.
https://steamdb.info/blog/source2-announcement/