Michael Hobson of Classic Records maunfactured records from 'Classic Clarity' vinyl (Clarity SVP II), which is clear and did not use carbon black.
Here's a mildly informative
Stereophile article on Clarity pressings.
Some had a single piece of music in 45rpm on one side and 33-1/3rpm on the other.
Reviews were somewhat mixed. I have a copy of Shoshtakovich's Symphony No.5 from Pavel Kogan and the Moscow State Symphony produced by Classic and pressed on Clarity vinyl in a 33-1/3 issue. I can't tell how much difference is made by the clear vinyl, but the sonics are very nice, the performance is excellent.
Carbon black contains some amount of metal and is a purported reason for LP demagnetizers, such as the one from Furutech.
There are a limited number of vinyl pellet makers. Hobson probably had to have a special order to get pellets without carbon black.
There can be other stuff in vinyl to aid thermal buffering and mold release during the pressing process, such as: dibasic lead stearate or cadmium or other esters of stearic acid. Formulations vary over the years; some vinyl is 'cleaner' (less noisy) than others.