This will get you in the ballpark with 1 minute world builds with a higher number of evil biomes. The actual evil biome effects may not include re-animation (and with the current unkillable hair/woolreanimated-head bug, some would advise against seeking it out).
On the main DF menu, use the "Design New World With Advanced Parameters" option.
On that screen, use the up/down arrows to choose the world size (POCKET REGION is what you want) and then use 'e' to "Enter Advanced Parameters".
On that screen:
The first page has "Year to begin Checking for MegaBeast Percentage", hit Enter and set that to 250.
Page Down about 5 times to find "Number of Secret Types", hit Enter and set that to 1000.
Page Down to find "Desired Evil Square Count in Small Subregions", hit Enter and set that to 1000 (it will cap it at the max).
Hit ESC to back out of the Advanced menu.
Hit F6 to save the world params (this will only effect these custom world builds).
Hit Enter to generate the world.
The result should be a relatively evil region with a tower or two for some extra undead incursions
move the cursor through the world and check out purple and red squares. You are looking for
one or more "Dark Goblin Fortress" within 10 of...
one or more "I" (necromancer towers)
and with some red terrains (red=terrifying biomes and purple=lesser evils )
"Dark Goblin Pits" will not matter.
Build a new one with 'a' and 'Enter' if it looks "meh"
If the world fits those conditions then hit 'p' to export and verify there are a lot of goblins, then try it out and see what the biomes offer. There is also an option to decrease mineral scarcity in the advanced options (i've seen a fair number of no-metals evil biomes) and this is important because the Dark Goblin Fortress sends goblins based on
goblins available to be sent
fortress wealth (craft weapons/armor or cook masterpieces)
number of dwarfs (I think others have said you need 80?)