If you search for ashless AW/FMs, you'll find companies that sell and/or manufacture a variety of additives, including the ashless type for all sorts of purposes.
This should have read ashless AW/EP. I don't know how much ashless FM is on the market. I was recently on the Chevron-Oronite website and they said that they offered their HDEO additive packages that include a unique friction modifier specifically developed for heavy duty oils. So at least there's that, but I'm pretty sure I've seen other additive companies that manufacture ashless FMs.