The following template files are available with your Maya installation on the Windows platform, and can be found in the default user templates folder (<Documents>\maya\RSTemplates).
The following template files can be used to matte out objects that have the aiStandardSurface shader assigned:
RenderLayerExample-Arnold.json: Import this template to create a layer with two collections. The first collection adds objects to the layer; the second collection specifies the object(s) that you want to matte out, and has a corresponding shaders subcollection and a matte override.
MatteOverride-Arnold.json: Import this template to create a shaders subcollection for the objects that you want to matte out, and a corresponding matte override.
The following template files can be used to create overrides to set specific cameras as renderable or non-renderable.
RemoveRenderableCameras.json: Import this template if your cameras are set as renderable in your scene, but you want to set a subset of these cameras as non-renderable in your layer. For example, if camera1, camera2, camera3, camera4 are all set as renderable in your scene, you can create an override to set camera1 and camera2 as non-renderable in Layer1.
After you import this template, add the cameras that you want to set as non-renderable to the Remove_Renderable_Cameras collection.
SetRenderableCameras.json: Import this template if your cameras are set as non-renderable in your scene, but you want to set a subset of these cameras as renderable in your layer. For example, if camera1, camera2, camera3, camera4 are all set as non-renderable in your scene, you can create an override to set camera1 and camera2 to renderable in Layer1.
After you import this template, add the cameras that you want to set as renderable to the Add_Renderable_Cameras collection.