Afaik, the standard orings are exactly the same material as in standard orings. Obviously, you can get stuff made of other materials, but your average black rubber oring isn the same material, no matter where you buy it. And I know for a fact that in the early days of body modification, when people were making their own plugs, they used orings from a hardware store. There weren’t any specialty ones at all.

Now, over the years, there arose more decorative options, which often required a change in materials. Can’t make glowy orings out of the same rubber, you dig? But the typical ones you find on mass produced plugs are ordered from the same places that the hardware store ones get made.

I’m not saying that all plug makers order from the same places, just that when you’re churning out thousands of plugs, you either make your own orings, or you’re ordering them from somewhere. When that somewhere is also mass producing their orings, you are going to end up ordering what they make unless you’re ordering enough to merit them setting up another production line for your needs.

Again, afaik, there isn’t a piercing specific oring maker that’s selling to plug makers. It’s all coming from the same suppliers in China for the most part.

The caveat: been over a decade since I was hanging out with people that were serious about body mods enough to be making their own stuff and ordering supplies in bulk. Shit could have changed since then. I doubt it, but if anyone that’s currently making plugs on a large scale says otherwise, they’d know better than I do.