Take 20: Creating a constrained setting

Over at the excellent They Might Be Gazebos blog, a challenge was thrown down. Create a sandbox setting based solely on twenty monsters. I think this is a pretty awesome idea. I like the idea of constraints spawning creativity. I think a setting with only twenty common monsters would likely hold together somewhat better than one with everybody in the book. And, it would help to strongly reinforce character build decisions like a ranger's favored enemy.

So, here's my list of 20. I'm going with the d20srd list, for simplicity's sake.

First, I'm going to assume that the core races are included for free. I'm also going to assume that normal animals are included for free. (Which is also kind of awesome, as I like using normal animals.)

I'm going to start with hacking off an entire class of monsters: extra-planar. No elementals, no angels, no demons, nothing. It's easy to eliminate them, and it simplifies the cosmology. Certain divine messengers may exist, but they serve solely as representatives of the gods, and cannot take a direct hand in any events.

We are going to cover several iconic niches. First, we will need cannon fodder. I am going to go with the orc on this one. But, not just the orcs as described in the text. There are a huge variety of mongrel humanoids out there, the result of various cross-breeding encounters, magical experiments, and ancient curses. You might meet lizard men, tiger men, pig men, or terrible crosses of all three. But, despite these superficial differences, all of these creatures will be called orcs, and will use the orcish stats. I am also going to include the ogre, to represent really big orcs.

Monster #1: Orc. These are Medium-sized humanoids with more muscle than brains, and few social skills.
Monster #2: Ogre. These are Large-sized humanoids with even more muscle, even fewer brains, and no social skills.

The next niche is undead. They are pretty important, I think. Oddly enough, there aren't that many on the SRD list there. But, I think I can find some good ones.

Monster #3: Zombie. Conveniently, this is presented as more of a template than a single monster. But, mostly, they are the mindless shock troops of the undead, and the result of animate dead.
Monster #4: Ghoul. I love ghouls. Though, honestly, I might use the ghast stats, just to give more of a bridge between the lowest and highest forms of undead.
Monster #5: Spectre. I actually prefer spectres to either vampires (terribly overdone) or liches (too powerful to really work in most scenarios). I would add a couple of notes that necromancers and priests of Vecna compete to become spectres rather than dying, and that spectres retain spell-casting abilities.
Monster #6: Shadow Mastiff. Yeah, I know, it is statted as an outsider. I want to change it to undead and make it the loyal servant of the spectre.

With this kind of scenario, we need a "big bad." A creature that lurks in the wasteland and can challenge civilization itself. Demons are an obvious choice, but we've already cut those out. For innovation's sake, I'm going to not use dragons. There are a few very interesting choices. Aboleths are pretty classic. So are rakshasa and yuan-ti. But, there is one particular choice that I want to go for, because I will never be able to use it. You see, my wife has really terrible arachnophobia.

Monster #7: Aranea. With class levels to buff these up, they can be serious bad-asses. Especially with the native shape-shifting.
Monster #8: Drider. Rather than being all about the drow and Llolth, these are the fighters to the aranea mages.
Monster #9: Ettercap. These are a debased relative of the aranea, like goblins are to humans.

With the spider-folk as the big bad, I'm going to want to continue the buggy theme. So, a few other classics to pull out:

Monster #10: Ankheg.
Monster #11: Behir. I'll make it a little more like a centipede and a little less like a dragon.
Monster #12: Chuul.
Monster #13: Remorhaz.
Monster #14: Phase Spider. Yeah, technically this gets into extraplanar stuff. But, it is too perfect to not include with the aranea.
Monster #15: Spider Eater. Okay, this is actually kind of a silly creature. But, if the humans are fighting the spiderfolk, they'd breed hunter pets. The fact that it comes with rules for using as a steed is a bonus.

I'm bummed that I don't have access to a few other classics. In particular, I'm missing the carrion crawler. But, I'm sticking to the list I have, bizarre as it is.

Now to round out the list with a few other classics that just need to be in the world.

Monster #16: Stirge. Nothing is better for harassing low-level parties.
Monster #17: Sprite. You need some kind of fairies, and these are pretty iconic.
Monster #18: Gargoyle. Gargoyles are awesome. If you don't believe me, watch Blink.
Monster #19: Shambling Mound. I figure we should have a plant creature.
Monster #20: Black Pudding. We should have an ooze.

Wow. I am very glad I went the route of knocking out extraplanar, and knocking out dragons. That cut my list down to a manageable size. Even so, there were several monsters I really wanted to include. And, there are a few that the absence is going to be surprising to players (e.g., lycanthropes). I think that sticking to this list will strongly reinforce some themes, keeps things very manageable, but still has some really nice variety.

I might even try a different list, and see how it works.