Just getting this up, so the description will be short for now. Double HSV Film Grain was originally a work-around that simulates Photoshop's film grain filter. It has become more than that, though. Simple to use, it has a few features that go beyond simple noise filters. There is the option to either compress the layers down to the original, or keep the three separate working layers to be manipulated individually. There is also an option to limit the working layers to just two noise layers.
Still testing it for bugs, so any input would be appreciated.