This latest Steam Client Beta will likely be rather nice for some of you, as it fixes an issue I've seen repeatedly complained about.
The Linux-specific bug where Steam wouldn't create desktop shortcuts and application menu shortcuts has been fixed. While I don't use either, it's nice to see little nuisances like that fixed for those that do use them. That bug has been open on their GitHub since June, so people have been waiting a while on it.
They've also now implemented support for automatically downloading pre-compiled GPU shaders for Vulkan games and applications on Steam. This can help first-load times and stuttering, so hopefully this is another step that can help Linux game performance in future.
There's also a bunch of changes to Steam Input which includes: a section to easily see exported gamepad configurations from your friends, they've added support for "several dozen Xbox controllers" using data from users which should enable them to work better on Linux & Mac, support for more PS4 gamepads and more.
One bug I hope they sort sooner rather than later, is the broken Steam Screenshot tool. Sometimes it works, sometimes it completely fails. This bug has been around since at least April on their GitHub and it's really quite annoying.