2k PBR Metal/Rough: BaseColor, Normal(OpenGL), Normal(DirectX), Roughness, Metallic, AO.
1k Unity Built-in: AlbedoTransparency, AO, MetallicSmoothness, Normal.
1k Unity HDRP: BaseColor, MaskMap, Normal.
1k Unreal Engine: BaseColor, Normal, OcclusionRoughnessMetallic.