|Each one of these is a 3HD creature|
with multiple attacks, regeneration,
and tasty snacks.
Monsters. Horrible things. Lots of HP. Not much xp. And unless you happen across a lair - not much gp either. Only thing worse than monsters? Math. Let's do some monster math.
6) D12 - MONSTER LIST1 - DL-2 HD 7 - DL HD
2 - DL-1 HD 8 - DL HD
3 - DL-1 HD 9 - DL+1 HD
4 - DL HD 10 - DL+1 HD
5 - DL HD 11 - DL+2 HD
6 - DL HD 12 - DL+2 HD
(DL = Dungeon Level)
We're told (in Mentzer Basic) that in general, a dungeon should work like this: monsters are encountered mostly on the level of the dungeon equal to their Hit Dice. And the difference between the dungeon level and HD is usually no more than 2. So that is what the above table means. Slightly skewed in favour of higher level over lower level, because, hey, players don't complain enough about dying horribly and repeatedly.
How to use this table? Fill in each entry with an individual critter of the indicated hit dice. Special abilities are ignored, so a 2HD** creature is still 2HD. If you want a creature to be more common, fill in multiple slots with the same creature. You're welcome (and instructed in the rules) to hand place monsters outside those ranges however you wish. But for purposes of generating a random dungeon, the core stable of monsters should follow the guidelines above.
If you wanted random monsters too...well I'm sure you're clever enough to find or make a table of monsters sorted by hit dice to roll on.
This table is for the specific placement of monsters as indicated on table 4, but can double as a wandering monster/random encounter table.
Next up is treasure, in which I hope to use the above table to help generate it in such a way as it all nicely scales no matter what dungeon level you're on.
Side note: How many individual monster types do you like to put in your dungeons? I feel that 12 is a good number. It has room for a couple of factions, some incidental wild beasts and one or two surprises. More than that and it can become cumbersome to figure out how they all interact within that dungeon environment.