The question is which ones might be appropriate for you. (technically there are vitamins and vitamin like things that are not herbs but not precription meds either)
If you are not into doing the research, finding a good practitioner is the way to go. Of course, even a good practitioner may have the belief PMO doesn't cause issues, a lot of people will automatically assume that has no bearing on your issues. Or say someone thinks it's not biological at all and you just need to do talk therapy and meditate.
I think what might help might not be obvious. For example there might be some stuff that you might take that's good for you and/or your mind, but it doesn't necessarily have a direct impact on porn addiction - but maybe it takes the level of stress down a bit. Life doesn't work on a do this for that basis only, sometimes it might take a combination of a lot of things but that means you gotta look at things in detail, and it make take time and consistency in trying that set of things to start seeing results.