Moved the create shader graphs in under Create -> Shader -> PBR shader / Unlit Shader / Sub Shader

They also create proper defaults. PBR creates a PBR Master, Unlit creates an Unlit Master

MaterialGraphProject/Assets/UnityShaderEditor/Editor/AssetCallbacks/CreateShaderSubGraph.cs

 {
     public class CreateShaderSubGraph : EndNameEditAction
     {
-        [MenuItem("Assets/Create/Shader Sub Graph", false, 208)]
+        [MenuItem("Assets/Create/Shader/Sub Graph", false, 208)]
         public static void CreateMaterialSubGraph()
         {
             ProjectWindowUtil.StartNameEditingIfProjectWindowExists(0, CreateInstance<CreateShaderSubGraph>(),

MaterialGraphProject/Assets/UnityShaderEditor/Editor/AssetCallbacks/CreatePBRShaderGraph.cs

+using System.IO;
+using UnityEditor.ProjectWindowCallback;
+
+namespace UnityEditor.ShaderGraph
+{
+    public class CreatePBRShaderGraph : EndNameEditAction
+    {
+        [MenuItem("Assets/Create/Shader/PBR Graph", false, 208)]
+        public static void CreateMaterialGraph()
+        {
+            ProjectWindowUtil.StartNameEditingIfProjectWindowExists(0, CreateInstance<CreatePBRShaderGraph>(),
+                "New Shader Graph.ShaderGraph", null, null);
+        }
+
+        public override void Action(int instanceId, string pathName, string resourceFile)
+        {
+            var graph = new MaterialGraph();
+            graph.AddNode(new PBRMasterNode());
+            File.WriteAllText(pathName, EditorJsonUtility.ToJson(graph));
+            AssetDatabase.Refresh();
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/AssetCallbacks/CreateUnlitShaderGraph.cs

+using System.IO;
+using UnityEditor.ProjectWindowCallback;
+
+namespace UnityEditor.ShaderGraph
+{
+    public class CreateUnlitShaderGraph : EndNameEditAction
+    {
+        [MenuItem("Assets/Create/Shader/Unlit Graph", false, 208)]
+        public static void CreateMaterialGraph()
+        {
+            ProjectWindowUtil.StartNameEditingIfProjectWindowExists(0, CreateInstance<CreateUnlitShaderGraph>(),
+                "New Shader Graph.ShaderGraph", null, null);
+        }
+
+        public override void Action(int instanceId, string pathName, string resourceFile)
+        {
+            var graph = new MaterialGraph();
+            graph.AddNode(new UnlitMasterNode());
+            File.WriteAllText(pathName, EditorJsonUtility.ToJson(graph));
+            AssetDatabase.Refresh();
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/AssetCallbacks/CreateUnlitShaderGraph.cs.meta

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+  externalObjects: {}
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MaterialGraphProject/Assets/UnityShaderEditor/Editor/AssetCallbacks/CreateShaderGraph.cs

-using System.IO;
-using UnityEditor.ProjectWindowCallback;
-
-namespace UnityEditor.ShaderGraph
-{
-    public class CreateShaderGraph : EndNameEditAction
-    {
-        [MenuItem("Assets/Create/Shader Graph", false, 208)]
-        public static void CreateMaterialGraph()
-        {
-            ProjectWindowUtil.StartNameEditingIfProjectWindowExists(0, CreateInstance<CreateShaderGraph>(),
-                "New Shader Graph.ShaderGraph", null, null);
-        }
-
-        public override void Action(int instanceId, string pathName, string resourceFile)
-        {
-            var graph = new MaterialGraph();
-            graph.AddNode(new PBRMasterNode());
-            File.WriteAllText(pathName, EditorJsonUtility.ToJson(graph));
-            AssetDatabase.Refresh();
-        }
-    }
-}