The official Vulkan API Conformant Products list from The Khronos Group recently had Valve's Steam Machine appear on it - so a release is likely quite soon.
HID Remapper is a useful open-source programmable adapter for USB input devices, with a recent release adding support for Valve's new Steam Controller.
As a bit of a PSA - you might want to ensure you're rather careful with Valve's new Steam Controller charging Puck. Keep anything conductive away from it.
Valve are (obviously) trying to get the New York lootbox lawsuit dismissed, with some interesting arguments to defend lootboxes in games like Counter-Strike 2.
Bringing together the worlds of twin-stick arcade shooters with crafting and exploration, Veridian Expanse is another indie game with a demo worth a go.
Valve released the latest small stable update to their Linux distro with SteamOS 3.7.25, along with SteamOS 3.8.5 Beta bringing extra fixes and enhancements.