The notes for Unreal Engine 4.22 have recently been released, and things are starting to look a lot brighter for Nvidia's RTX series of graphics cards.
A list of supported features include:
Real-Time Ray Tracing and Path Tracing (Early Access)Added ray tracing low level support.Implemented a low level layer on top of UE DirectX 12 that provides support for DXR and allows creating and using ray tracing shaders (ray generation shaders, hit shaders, etc) to add ray tracing effects.Added high-level ray tracing featuresRect area lightsSoft shadowsReflectionsReflected shadowsAmbient occlusionRTGI (ray traced global illumination)TranslucencyClearcoatIBLSkyGeometry typesTriangle meshesStaticSkeletal (Morph targets & Skin cache)Niagara particles supportTexture LODDenoiserShadows, Reflections, AOPath TracertUnbiased, full GI path tracer for making ground truth reference renders inside UE4
Along with improved DLSS - this hopefully indicates that 2019 will end up with more than just two games supporting Ray Tracing.