I get great foamy head from Fawcett oat malt. Nobody knows exactly how much gluten it might be contaminated with, but many are fine with it. You can search for some discussions around here about it.
In my experience head and mouthfeel are fine as long as you use a decent amount of grain and add some maltodextrin.
Primary: Fish Face IPA
Secondary: Perry, Plum Wine, Peach Wine, Mystery White Blend Wine
Bottled/Kegged: GF Graff, Accidentily Imperial Stout, Apricot Wine, Cider, All-Juice Apple Wine, All-Juice Strong Cider, Sparkling Plum Wine, Experimental Honey Steam
Coming soon:, Blackberry Wine, GF Pale, GF Braggot