With the release of Unity 2018.3, Shader Graph introduces a new Master Node for the High Definition Render Pipeline (HDRP).
This new Master Node (called Lit Master) makes many of the advanced shading features found in HDRP accessible in Shader Graph!
These HD Lit Advanced Features, or HD Lit AF, include coat-mask, iridescence, translucency, subsurface scattering, and anisotropy.
Unity released a blog post that will introduce you to some of these advanced features, and show you how to use them to create beautiful assets in HDRP using Shader Graph. You can download the sample project created for this blog post from GitHub.
The simple project contains a bonsai tree and butterfly that make heavy use of iridescence and translucency.
For more details, visit the Unity blog.