Things people like:
Assume all of these are high quality (There's an excellent discussion on quality at
http://havenandhearth.wikia.com/wiki/Quality):
Soil (For making high quality trees, and in turn high quality wood)
Clay (For making high quality kilns, and in turn high quality bricks)
Water (For making high quality food primarily)
Food (For decreased time required to stat up)
A special consideration is for metal, particularly iron. Even iron of very low-grade will trade for a LOT on the open market.