Venezianico do an ultra-black dial, hard to tell what it looks like IRL though.

https://www.venezianico.com/products/redentore-ultrablack-1221510c

Funny you should mention this. I had a post in the last week where I was discussing my preference for black dial watches… .so had this handy:

Frederique Constant Classics ($800)
Longines Conquest ($1700)
Ball Fireman Enterprise ($1000)
Sinn 556 I ($1600)
Traska commuter ($600)
Oris Big crown ($1500)
Tissot PR 100 ($600)
Hamilton Jazzmaster ($600)
Citizen TSUYOSA ($360)
Grand Seiko SBGA203 ($4800)
Grand Seiko SBGH301 ($6900)
Seiko SARB033 (~$500 used)

There are some seikos that have deep inky black dials. I can’t remember how they are called.

Edit: it’s called urushi dial.