Without arguing about what is and isn't folk, these at least are not traditional:

PeterA beat me to it but I was going to say Steve Earle. Almost anything by Steve Earle.

Second "Sixteen Tons", "Dark as a Dungeon", and "Coal Tattoo". Add Wheeler's "Red-Winged Bird", as well.

Norman Blake's "Billy Gray"
Lucinda Williams' "Concrete and Barbed Wire"
Gillian Welch "Everything is Free" and "One Morning", among many others
A lot of stuff by Slaid Cleaves
OCMS "Wagon Wheel"