tl;dr make scattered cities like meresauge give more metal or fabric and rauchwolke give more threads or food
can do this for gunpowder, leviathan skin, etc.
#have cities give more of 1 resource then another
tribal flower
the reason this is especially good with the awful gbmm idea you guys are adding is beacuse it creates hotzones for lategame players who need to farm reinforced leather strips for t4 cannons