unity find gameobject with layer

// This will retrun the layer mask of the specified gameObject
gameObject.layer

// You can as well modify this value through code
gameObject.layer = LayerMask.NameToLayer("SomeOtherLayer")

void Start()
{
    GameObject objByName = FindInActiveObjectByName("Cube");
    GameObject objByTag = FindInActiveObjectByTag("CubeTag");
    GameObject objByLayer = FindInActiveObjectByLayer(LayerMask.NameToLayer("CubeLayer"));
}