Youｴll find the, plenty. And I do not understand the need - normal arrows donｴt use uo, so the only reason for arrowheads would be crafting the fire and poison versions, the stunning ones are made from teeth. You should have so much money by now that it is MUCH easier to simply buy arrows if need be. To give an indication - 70,000 entering Luculla map, 200,000 entering Phantom Forest map. Without any specific effort besides bartering 3 and raising attitudes of preferred traders to 100.
Regards,
Thorsten
