I still have the list with me for when I was developing each monster.
1. DUL - Super Quiet
2. Droner - Is cloaked
3. Fly Man - Can go up ventilation shafts
4. Squid Made of Tar - Can shoot tar that blinds the player
5. Fish Freak - Lays goo traps that can immobilize the player for 4 seconds
6. Martian - Can shoot two lasers every couple of seconds
7. The Reptile - Can charge at the player during a chase
8. The Blob - Lays keycard traps on the floor. When approached, it will spawn The Blob at it's location.
9. Rouge Tinfoil Robot - Can shoot one laser every couple of seconds but moves faster than The Martian
10. The Slime - Can go up ventilation shafts and use the small vents on the walls to spawn from them. (It's slower than The Fly Man I think)
11. Dead Man - Can scream at the player during a chase, which stuns the player for about 2 seconds.
12. Cheeva - Can sprint every 45 seconds outside of a chase to move around the map faster.
13. Xenomorph (From ALIEN) - Can go up ventilation shafts and is faster than The Slime and The Fly Man
14. Berry The Bear (From Shopping Nightmare) - Can spawn Berry clones. When approached, will spawn Berry The Bear at it's location.
15. Monster Coach (From L4D2) Can charge during a chase but his charge lasts longer than The Reptile.
16. Uber Jason - (From Jason X) Cannot be killed and can chase the player a lot longer than any other monster. But is the slowest of all the monsters.
17. Dave Micromonster (That's me!) - Shoots two hamburgers every couple of seconds.
Hope this helps!