Resources are used for a variety of things. From upgrading buildings, to building houses, to being used in Dreamforging to create equipment for your units.
The three main resources are Stone, Metal, and Wood. There are also several others.
List of Resources[]
Hermetic Copper
Brilliant Sapphire
Magus Ash
Blood Iron
Cursed Opal
Mountain Beech
Windigo Silver
Dark Ruby
Grand Maple
Sacred Gold
Eerie Emerald
Royal Pine
Ethereal Platinum
Skull Diamond
Holy Oak