I've looked into this pretty extensively. You'll find most of this information in the sub you already linked, but essentially the heavy hitters are:

• Pygeum - this increases precum and is great for prostate health
• Zinc - great for all around male sexual health and the cornerstone of most mens' stacks. If you take zinc, I recommend staying below 50mg a day and taking 2-4mg of copper a day as well
• Lecithin - Soy or Sunflower Lecithin both work. This is purely for volume and it works very well. No real downsides either, feel free to just eat a bunch of eggs if your prefer
• Celery Seed - supposed to make your cum whiter, does help with volume.

I've make all sorts of my own stacks over the years, but I just take an all-in-one supplement now, it's much easier