Within Reagent, the Reagent subtype gets its own tracked table here. Each row below carries its own price-history page rather than sharing a single blended entry.
Reagent listings clear and replenish at whatever pace the in-game market sets; some subtypes trade in volume, others sit static for stretches. The price-history chart on each row's detail page makes that pattern visible at a glance.
The "Browse subcategories" links on the parent Reagent page list every other subtype if you want to compare markets side by side.