Aromatics
There is value in discovering a category: A category reveals the existence of other adjacent categories.
Especially — "what is in, and what is out".
"Aromatics" in cooking was a key category for me: To impart flavour and aroma to food, this is the set of vegetables and herbs to use.
That implies there are other vegetables and herbs that have a different purpose.
And now I have knobs to play with.