Vulkan

Vulkan is a low-overhead, cross-platform API, open standard for 3D graphics and computing developed by Khronos Group, a successor to OpenGL.

Games that supports Vulkan:

• Half-Life 2 (added since 2022 Steam Deck update)
• Portal (same as HL2 case)
• Left 4 Dead 2 (since the June 15, 2021 update)
• Portal 2
• Counter-Strike: Global Offensive (Linux only)
• Dota 2
• Artifact
• Half-Life: Alyx (since version 1.3, released in May 16, 2020)