Ronan Tynan performing "The Town I Loved So Well"
Arlo Guthrie - "City of New Orleans"
Willie Nelson, et al - "Pancho & Lefty"

While none are likely considered folk songs, each has a haunting, evocative quality that I happen to like and lyrics and imagery that play on your mind.

I recall the first time I ever heard "Johnny, I Hardly Knew Ye," done by a local singer named Jon Adams in a coffee house in Fresno, CA in around 1959-60. You could have heard a pin drop.