You can use the following table to improvise a monster without creating a stat block. Most of these use the high numbers from the Gamemastery Guide.
Creature Numbers
Saves/Perception | ||||||||
Level | Skill | AC | High | Medium | Low | HP | Strike | Spell DC and Attack |
–1 | +5 | 15 | +8 | +5 | +2 | 9 | +8 for 1d4+1 | 16/+8 |
0 | +6 | 16 | +9 | +6 | +3 | 18 | +8 for 1d6+2 | 16/+8 |
1 | +7 | 16 | +10 | +7 | +4 | 25 | +9 for 1d6+3 | 17/+9 |
2 | +8 | 18 | +11 | +8 | +5 | 38 | +11 for 1d10+4 | 18/+10 |
3 | +10 | 19 | +12 | +9 | +6 | 55 | +12 for 1d10+6 | 20/+12 |
4 | +12 | 21 | +14 | +11 | +8 | 75 | +14 for 2d8+5 | 21/+13 |
5 | +13 | 22 | +15 | +12 | +9 | 95 | +15 for 2d8+7 | 22/+14 |
6 | +15 | 24 | +17 | +14 | +11 | 120 | +17 for 2d8+9 | 24/+16 |
7 | +17 | 25 | +18 | +15 | +12 | 145 | +18 for 2d10+9 | 25/+17 |
8 | +18 | 27 | +19 | +16 | +13 | 170 | +20 for 2d10+11 | 26/+18 |
9 | +20 | 28 | +21 | +18 | +15 | 195 | +21 for 2d10+13 | 28/+20 |
10 | +22 | 30 | +22 | +19 | +16 | 220 | +23 for 2d12+13 | 29/+21 |
11 | +23 | 31 | +24 | +21 | +18 | 245 | +24 for 2d12+15 | 30/+22 |
12 | +25 | 33 | +25 | +22 | +19 | 270 | +26 for 3d10+14 | 32/+24 |
13 | +27 | 34 | +26 | +23 | +20 | 295 | +27 for 3d10+16 | 33/+25 |
14 | +28 | 36 | +28 | +25 | +22 | 320 | +29 for 3d10+18 | 34/+26 |
15 | +30 | 37 | +29 | +26 | +23 | 345 | +30 for 3d12+17 | 36/+28 |
16 | +32 | 39 | +30 | +28 | +25 | 370 | +32 for 3d12+18 | 37/+29 |
17 | +33 | 40 | +32 | +29 | +26 | 395 | +33 for 3d12+19 | 38/+30 |
18 | +35 | 42 | +33 | +30 | +27 | 420 | +35 for 3d12+20 | 40/+32 |
19 | +37 | 43 | +35 | +32 | +29 | 445 | +36 for 4d10+20 | 41/+33 |
20 | +38 | 45 | +36 | +33 | +30 | 470 | +38 for 4d10+22 | 42/+34 |