New biomes are created when there is sufficient variance, compared to those nearby.

To get hundreds or thousands of biomes, you need to use the largest possible variance (3200) on elevation, rainfall, temperature, drainage, volcanism and savagery.

Volcanism and savagery cause unexpected behavior with elevation and dwarven civilization placement, so they can be omitted just to get an idea of what I mean.

Specifically, try these, on a copy of a default "Small Region":

End Year: 150

Cull Unimportant Historical Figures: Yes

Reveal All Historical Events: No

Minimum Elevation: 100

Maxiumum Elevation: 360

Elevation X-Variance: 3200

Elevation Y-Variance: 3200

Minimum Rainfall: 0

Maximum Rainfall 100

Rainfall X-Variance: 3200

Rainfall Y-Variance: 3200

Minimum Temperature: -36

Maximum Temperature: 78

Temperature X-Variance: 3200

Temperature Y-Variance: 3200

Minimum Drainage: 0

Maximum Drainage: 100

Drainage X-Variance: 3200

Drainage Y-Variance: 3200

Minimum Volcanism: 0

Maximum Volcanism: 0

Volcanism X-Variance: None

Volcanism Y-Variance: None

Minimum Savagery: 0

Maximum Savagery: 0

Savagery X-Variance: None

Savagery Y-Variance: None

Minimum Mountain Peak Number: None

Minimum Partial Edge Oceans: None

Minimum Complete Edge Oceans: None

Minimum Volcano Number: None

Number of Demon Types: None

Number of Night Troll Types: None

Number of Bogeyman Types: None

Number of Vampire Curse Types: None

Number of Werebeast Curse Types: None

Number of Secret Types: None

Number of Regional Interaction Types: None

Number of Disturbance Interaction Types: None

Number of Evil Cloud Types: None

Number of Evil Rain Types: None

Desired Good Square Count in Small Subregions: 4225

Desired Good Square Count in Medium Subregions: None

Desired Good Square Count in Large Subregions: None

Desired Evil Square Count in Small Subregions: 4225

Desired Evil Square Count in Medium Subregions: None

Desired Evil Square Count in Large Subregions: None

All the "Minimum Initial" and " Minimum Final" values: None

All the "Minimum Number of ... Squares values: None

Try those, and initially, change the setting:

Playable civilization Required: to No

This will give you an idea of what kind of world to expect.

---

Upon gen'ing this world, you'll see tremendous variety in biomes next to each other. Deserts next to swamps, glaciers next to scorching jungles and so on.

However, without a place to put the dwarven civilization, it's just a pretty picture.

So to make that happen, change:

Elevation X-Variance: None

Elevation Y-Variance: None

Elevation Mesh Size: 8x8

Elevation Weighted Range (0-20): 8

Elevation Weighted Range (20-40): None

Elevation Weighted Range (40-60): None

Elevation Weighted Range (60-80): None

Elevation Weighted Range (80-100): 2

Playable civilization Required: to Yes

So what did that do? It change the elevation of the world so that 8 out of 10 times (80%) of the elevations would be between the bottom 0 and 20% of the min/max values. While that sounds a bit confusing, think of it like slicing the entire above-ground map into 5 slices of the same size. Now you can apply weights to those slices, so that elevations will end up within whatever slice you want more than others. If you imagine five slices of bread stacked like a big sandwich, that's the mental picture you want.

Think of the the 0-20 slice as the bottom. You've set your minimum Elevation to 100, overall and your maximum elevation to 360, overall. That means between 100 and 360 is a valid elevation range. 260 divided by 5 is 52. So, the first slice will be 100-152 elevation. 80% of the time, the elevation will be in that range, because we've applied a weight of 8 to to that slice.

So what is that 80-100 weight of 2 doing? That's allowing mountains to form,

so dwarves can build their mountainhome.

The "top slice", that is, the 80-100 weighted range, is for 360 (the max we've specified) to 308 (360 minus 52). That means, 20% of the time (weight of 2) elevations will be in the range of 308-360. Without variance on elevation (we changed it from 3200 to None) there is no randomization/scattering of those values. They are clumped together. The amount of clumping is affected by the Mesh Size. We want big clumps of mountains, so we pick the largest mesh.

Why do we want big clumps of mountains? We don't want our mountains to be classified as small subregions. Small subregions are the ones that are getting the evil and good biomes. Medium sized subregions (in this case, our mountains) won't be evil or good, which is what dwarves need.

Essentially this creates "elevation islands" of mountains where the dwarves can start, and larger lower elevation regions where the evil and good biomes can thrive in variance with temperature, rainfall, and drainage.

There is no need to use any third party software to achieve a huge number of variant subregions with evil/good, with this method. If you want some more detailed instructions, or if any of this is unclear, reply or PM me.

All of this is for 34.10 (should work in 34.11, but not where I tested it)