For dark, i like Meinl. But not their actual Byzance Dark line.
most people consider their Byzance line as a whole to be “darker”, but I personally don’t think it’s that dark. Check it out, though. Might be what you’re after. The dual series is amazing. Not a huge fan of the way they look, but the sound and feel is unmatched IME.
Zildjian’s K custom darks aren’t all that dark to me, but definitely more tame than their other offerings. They also got some K Special Dry cymbals available. You can check those out too.
as for Sabian, I’ve never had any experience with them. But they are always kinda bright and clangy IMO. They have that new HHX Complex line, that’s supposed to be a little more… well, complex. And “dark”.
Larger sizes could also be a consideration. I personally like to stay 18”+.