Below are pictures of the monsters used in Monster Evolution mod. Mostly are from Goeppinger' Iniquitous: Monsters - http://www.unreal.shaungoeppinger.com/monsters.html. Also, I have posted similar pictures at ModDB - http://www.moddb.com/groups/killing-flo ... 1#imagebox.
NOTE: Click on top of picture for larger view.
The monsters are (starting from the front then towards the back, and from the right going to the left):
Quake - Chthon, Fiend, Scrag, Shambler, Shub Niggurath, Tar Baby, Vore.
Half Life - Alien Controller, Baby Head Crab, Bull Squid, Gargantua, Gonarch, Gonome, Grunt, Hound Eye, Nihilanth, Pit Drone, Shock Trooper, Baby Voltigore, Vortigaunt.
Xenomorph (Alien) - (Second row from front, fourteenth from left) Chestbuster, Drone, Facehugger, Queen, Praetorian, Predalien, Runner, Gnat, Rhinog, Stryker.
OSM - (Third from front) Skaarj Trooper, Skaarj Assassin, Skaarj Berserker, Skaarj Lord, Skaarj Scout.

Bio Buds And Seekers - (Fourth from right front) - Angus, Enlightened, Goro, Gun Walker, Mole, Shrike.
Dragons - (Next row from front) - Beam Dragon, Earth Dragon, Fire Dragon, Ice Dragon, Ion Dragon, Luvre Dragon, Nature Dragon, Wind Dragon.

These are just for reference.