>>1751038As anon said, most of those things are gone because they are extinct. For example the silphium plant was made extinct by the Romans. It was used for perfume, food, and medicine from its resin, but seems it was mostly used as birth control.
>https://www.straightdope.com/columns/read/2676/did-the-ancient-romans-use-a-natural-herb-for-birth-control/But if we're talking specifically about herbology secrets, there are a lot of plant remedies that the Amish use. There are plants Amish gather that if a person gets server burns and the areas of the body are wrapped in certain leaves, it reduces scar tissue. So if you want to learn some herbology the Amish would be a great source for research.