Green is unlikely, as that is the colour of skaven warpstone.
They could do that if they implement some sort of cursed weapon, I suppose.
I agree on yellow, though.
I could also, in the future, see white, or, odd as that sounds, black. And actual red, of course.
Glow… wth. I’d certainly prefer actual skins, or at least different particle effects. Why not have a fiery dagger/sword actually change the colour of the flame?