Im stuck at the second stage of the Goblin campaign where you need a blue goblin hat to make the next gong. However nothing will spawn except red, purple, and green goblins. Any ideas?
Belated welcome to the forum, @mrshihtzu 
I think that one is achieved with a goblin camp that has to spawn. Maybe it’s having trouble depending on your town layout.
If you upload your savefile we can take a look.
Might you be referring to kobolds?