Is There a Real Magical Knowledge That's Lost?

I feel like there's got to be some kind of knowledge. Even if it's just herbalism stuff, what certain plants can cure,. Just through trial and error over time. I mean, I'm sure that happens now. Pharmaceutical companies have sent people into very rural areas of the Amazon to research plant-streamed disease. If we're just spitballing, I guess it's also possible that an ancient civilization could have documented the orbit of a comet or something that is so far out and comes so rarely. We wouldn't be aware of it, possibly.