What world size are you using? Larger worlds give civilizations more time to expand their territories and grow their populations before they come into contact, leaving them less vulnerable to outside threats, particularly necromancers. And what's the number of desired civilizations set to? I'm guessing you probably set it pretty low to make it easier to get invested in each civ's history. I know I've done that, at least. If so, that may be the reason for your lack of goblins. Every world I've made lately has been overpopulated by goblins, and I haven't even been trying for that.
To get more goblin civilizations, you need more clowns bound to the surface world at the dawn of time. To get that to happen, you need plenty of gods with the appropriate spheres. To make sure that happens, you need at least a few different dwarf and human civilizations. Restricting the number of elf and kobold civilizations may also help by freeing up more civilization 'slots'.
So. Lowering the maximum number of caves to just 1 or 2 will reduce the number of possible kobold civs. Increasing the desired number of mountain regions will give more opportunity for dwarven civs to arise. Reducing the maximum rainfall and drainage to 60 or less will eliminate forests in favor of grasslands and swamps. Without forests, there will be no elves. More grasslands means more opportunities for humans. Although goblins civs aren't associated with a specific biome the way other races are, I have noticed a moderate preference for swamps, tundras, and glaciers. Probably just because other civs are averse to those locations.
Now, if you're willing to reduce the number of forests and elves, but you don't want to eliminate them entirely, then you may need to mess with the drainage and rainfall terrain meshes. Which I do not thoroughly understand proper use of. If you do, just remember to lower the minimum required high-drainage/rainfall squares. Otherwise the worlds will all get rejected.
And of course, to reduce the number of necromancers, you can just reduce the number of secret types.