Crimson Desert: Brimstone

Game8's gathering note puts brimstone on Deadfire Mountain, north of the City of Demeniss. You either harvest the fumes or kill Hexe Brimstoneback Crabs. A single visit is about 16 to 20 pieces. The fumes come back after you fast-travel away and return. I am not calling that an infinite timer, because no minute count is printed.

It is a crafting material. A sale price is not on the page, so the items table leaves that cell empty. This is a different loop from Aeserion Scales, which need a pot, and from the gold bars, which are chest loot.