There should be eight traders in the game. Have you found them all? Maybe killed one accidentally?
You can also trade with everyone you talk to by clicking on the TRADE button while in dialogue. Most characters have at least some food and a few gold; some have special arrows, scrolls and weapons; and a select few have some really useful stuff.
As well as the item you can craft using the recipe you find in the Blighted Village - and the spear you can construct after the Owlbear encounter, which I guess counts as crafting - you can make a potion by performing a particular operation on a particular herb.
Found two in the Druid's retreat, one of which buggers off after you kill the Goblin bosses, and one hanging about the Hag's hut. Not the foggiest where the others might even be. There aren't that many characters outside of enemies you can interact with. I'm doing a second playthrough, if I don't get bored at missing all the time and quit I'll look out for the other five.
