On my system using an AMD card (from lspci):
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti XT [Radeon HD 7970/8970 OEM / R9 280X]
I couldn't start any Vulkan games because no AMD vulkan drivers were installed.
I went with what Arch Wiki recommends:
https://wiki.archlinux.org/index.php/Vulkan#Installation
and installed the following packages:
- vulkan-icd-loader
- lib32-vulkan-icd-loader
- vulkan-radeon
- lib32-vulkan-radeon
For checking/testing vulkan I also installed:
https://wiki.archlinux.org/index.php/Vulkan#Installation
From what I can see so far, these packages are enough to solve the issue, at least for my particular card. Maybe also vulkan-intel could be considered for Intel graphics users.
But (and this might explain it) I also want to add that my card, which is a Radeon GCN 1.0 "Southern Islands" does not use by default the amdgpu driver, but radeon, so no Vulkan support by default.
To switch the card to the amdgpu driver, it has to be enabled explicitly.
https://wiki.archlinux.org/index.php/AMDGPU#Enable_Southern_Islands_(SI)_and_Sea_Islands_(CIK)_support
which I did in this case.
Maybe the Arch installation procedure is more fussy, sees this specific card and choose to not install the AMD Vulkan drivers since they're not needed by default, not sure here.
On the other hand (with amdgpu support enabled or not) on other distros tested so far, like SteamOS or Ubuntu, the AMD Vulkan drivers are installed regardless.