o3de-atom-sampleviewer/Materials/DefaultPBRTransparent.material

{
    "materialType": "Materials/Types/StandardPBR.materialtype",
    "materialTypeVersion": 5,
    "parentMaterial": "Materials/Presets/PBR/default_grid.material",
    "propertyValues": {
        "opacity.mode": "Blended"
    }
}