Here is my first table for AS&SH; roll 1d30 (number appearing in parentheses):
1.  Bat, normal (1d%)
2.  Rat, normal (2d10)
3.  Centipede, giant, black (3d4)
4.  Centipede, giant, pink (2d4)
5.  Rat, giant (3d6)
6.  Skeleton, animal, small (1)
7.  Snake, viper (1)
8.  Man, bandit (2d6)
9.  Orc, common (1d6)
10.  Skeleton (2d4)
11.  Skeleton, animal, medium (1)
12.  Snake, cobra (1)
13.  Stirge (3d6)
14.  Beetle, giant, fire (1d6)
15.  Cave-man (1d6)
16.  Ape-man (1d6)
17.  Man, wild berserker (1d6)
18.  Bat, giant (1d10)
19.  Ghoul (1d6)
20.  Green slime (1)
21.  Mustard mould (1)
22.  Orc, lieutenant (1)
23.  Snake, asp (1)
24.  Spider, giant, crab (1d4+1)
25.  Troglodyte (2d4)
26.  Zombie (1d6)
27.  Beetle, giant, bombardier (1d4)
28.  Lizard-man (1d6)
29.  Hyaena-man (1d6)
30.  Snake-man (1)
Design thoughts:  First, I made lists of all the monsters appearing in AS&SH by overall HD (1, 2, 3, etc.).  Second, I wrote the HD by each name.  Third, I looked at the environment list of monsters on p. 112 of the Bestiary and identified all the 1 HD and 2 HD type monsters.  Finally, I tried to order the list by least (1/4 HD) to greatest (2 + 2 HD) to simulate a natural distribution.  I know that green slime and mustard mould are basically static monsters, but in my mind a trap is no different than a monster.  Also, I know the orc lieutenant doesn't necessarily fit, but he could be wandering from somewhere else; I needed 30.    Let me know your thoughts; thanks!