Instead of me namedropping there's a pretty nice list
here with links to artist pages, samples and so on.
I'll highlight some special bands that I would recommend to check out first:
Sol Invictus is pretty classic for the genre. Dark folky songs with quite a bit of atmosphere.
Current 93 (as you already know) as they have a somewhat less folky and more psychedelic approach. The manic vocals can even be a bit creepy at times.
Forseti is one of the big ones as well. Rich on the folky elements as well and very atmospheric.
Of the Wand and the Moon is a personal favourite of mine. Very subtle music that takes some listens and concentration to fully get into. Some songs are more folky or dark than others but they are all very tranquil and atmospheric.
Eisenfaust has some excellent recommendations. Sol Invictus's "Kneel to the Cross" was of course covered by Agalloch and I like the original almost as much as that awesome cover. I'd throw Death In June or Nurse With Wound out there, but these are very acquired tastes.
