I've been really into the black metal/shoegaze sound lately. Since you like Alcest, I highly recommend checking out "Neon" by Lantlôs if you haven't already since it is also the work of Neige.

The weird thing about Alcest is that he swore blind he'd never listened to any shoegaze until people started making the comparisons. But there's similarities with black metal, in that the harsh tremolo-picked guitar sounds of the latter tend to suppress the rhythmic definition of playing, so the distance between that and wall-of-guitar shoegaze or even dark ambient music isn't so huge, unlike it would be with death or thrash metal.

Also worth mentioning would be Jesu. Some of that stuff makes me cry like a child.

EDIT: clarity

Yeah, see my Pitchshifter link above. There's a lot in common with both genres going for a kind of sensory washover.