TEXT: The following article provides DMs with a list of monsters
  from the MM that easily fit the setting of the Iron Kingdoms
  in terms of style, feel, and appropriateness, a second list of
  monsters that shouldn’t prove disruptive but might not fit the
  setting’s feel, and a third list of those monsters that if intro-
  duced would change the feel or setting significantly.
  The creators of the Iron Kingdoms strive to create an
  entirely new and fresh setting. This is not necessarily an
  extremely radical setting in all regards, as many of our creatures
  will be drawn closely from standard fantasy fare, but one will
  notice in cases where we have a similar appearing creature,
  we're usually reshaping it in some way and molding it to fit
  distinctly into the Iron Kingdoms; for example, we have gob-
  bers and ogrun instead of goblins and ogres, both of which
  are similar in many ways to the "standard" but also have dis-
  tinct differences. Iron Kingdoms elves and dwarves are also not
  identical to the ones described in the PH. A very good exam-
  ple from “The Witchfire trilogy” adventures are the treatment
  of skeletons and zombies from which thralls were created—
  just one of our takes on the traditional D&D undead.
  It should also be noted that Outsiders are incredibly rare.
  The Iron Kingdoms universe is significantly distinct from tra-
  ditional fantasy campaign settings, rendering many such mon-
  sters inappropriate, from the viewpoint of the Iron Kingdoms’
  creators. Due to this approach, you should not expect to see
  any of the following monsters mentioned in future Iron
  Kingdoms publications, but can rest assured that they can be
  used with little impact on the official setting or feel of the
  game.
  APPROPRIATE MONSTERS
  Allip
  Animated Object
  Ankheg (Ankhegs in the Iron Kingdoms would dwell in
  arid areas only, particularly the Bloodstone Marches)
  Assassin Vine (the Assassin Vine is related to the subter-
  ranean Cavewort)
  Bodak
  Chaos Beast (Chaos Beasts would only ever occur on
  Caen when a summoning spell goes horribly wrong)
  Choker
  Dwarf (the Iron Kingdoms has its own take on Dwarves,
  with the same ability scores but different culture)
  Elemental (Elementals rarely occur naturally in the Iron
  Kingdoms, and only appear from being summoned, and
  are not generally able to linger on Caen for long)
  Elf (the Iron Kingdoms has its own take on Elves)
  Frost Worm (Frost Worms would be some of the Nyss’
  most hated predators, and a possible favored prey)
  Ghoul/Ghast
  Gibbering Mouther (In the Iron Kingdoms there is
  rumored to be but a single Gibbering Mouther, a horrific
  magical mistake that is now said to exist within the bow-
  els of Ceryl’s undercity)
  Golem (These non-mechanikal constructs are seldom
  found in the Iron Kingdoms anymore, having been
  superceded by the likes of Steamjacks. However, a few of
  these old-fashioned constructs can still be found)
  Hag
  Homunculus (Much like familiars, Homunculi would be
  regarded with suspicion as possible indicators of pacts
  with Infernal masters, or devotion to black arts and
  Thamar-worship)
  Kraken
  Mohrg
  Nightshade (Nightshades would be undead servitors of
  the Infernals)
  Shadow
  Skeleton (Skeletons are still encountered in the Iron
  Kingdoms created by the regular animate dead spell, but
  are shoddy and inferior to Thralls)
  Spectre
  Vargouille (Vargouilles could come from the deepest pits
  of the Infernal planes)
  Wight
  Wraith
  Zombie (Zombies are still encountered in the Iron
  Kingdoms created by the regular animate dead spell, but
  are shoddy and inferior to Thralls)
  *Animals (Most natural animals can be found some-
  where on Caen)
  *Vermin (Only Monstrous Spiders of Small and
  Medium-size can be found in the deep wilds of Caen)
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  A Multitude of Monsters
  1
  Using Monster Manual® Monsters in the Iron Kingdoms™
  
  *Templates (Only the Ghost and Lich templates occur in
  the Iron Kingdoms, the latter considered inferior to the
  likes of the terrible Iron Lich)
  USABLE MONSTERS
  Basilisk
  Bulette
  Carrion Crawler
  Chuul
  Cloaker
  Cockatrice
  Darkmantle
  Destrachan
  Devourer
  Dire Animals
  Displacer Beast
  Doppleganger
  Ettercap
  Fungus
  Gargoyle
  Gray Render
  Grick
  Krenshar
  Manticore
  Mephits
  Naga
  Ooze
  Otyugh
  Purple Worm
  Remorhaz
  Roc (Although the Saqu of the Iron Kingdoms is largely a
  replacement for the Roc)
  Sea Lion
  Shadow Mastiff
  Shield Guardian
  Stirge
  Umber Hulk
  Will-o’-Wisp
  Worg
  Wyvern (Wyvern would be classified as a type of drake, and
  have no relation to dragons)
  Vermin
  DISRUPTIVE &
  INAPPROPRIATE MONSTERS
  Aboleth
  Achaierai
  Aranea
  Arrowhawk
  Athach
  Azer
  Barghest
  Behir
  Beholder
  Belker
  Blink Dog
  Bugbear
  Celestial
  Centaur
  Chimera
  Couatl
  Demon
  Devil
  Delver
  Dinosaur
  Dragon (The treatment of dragons in the Iron Kingdoms
  is vastly different than in normal D&D, and is an intrin-
  sic part of the setting)
  Dragon Turtle (the Dracodile fills the Dragon Turtle
  niche in the Iron Kingdoms)
  Dragonne
  Drider
  Dryad
  Ethereal Filcher
  Ethereal Marauder
  Ettin
  Formian
  Genie
  Giant (Giants exist in the Iron Kingdoms but are all
  unique)
  Giant Eagle
  Giant Owl
  Girallon
  Gnoll
  Gnome (Gobbers have taken the place of Gnomes in the
  Iron Kingdoms setting)
  A Multitude of Monsters
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  Goblin (Gobbers are Iron Kingdoms goblins)
  Gorgon
  Griffon
  Grimlock
  Halfling (Gobbers have taken the place of Halflings in
  the Iron Kingdoms setting)
  Harpy
  Hellhound
  Hippogriff
  Hobgoblin
  Howler
  Hydra
  Invisible Stalker
  Kobold
  Kuo-Toa (Kuo-Toa have been replaced with Bog Trogs)
  Lamia
  Lammasu
  Lillend
  Lizardfolk (Lizardfolk have been replaced with
  Gatormen)
  Locathah
  Magmin
  Medusa
  Merfolk
  Mimic
  Mind Flayer
  Minotaur
  Mummy
  Night Hag
  Nightmare
  Nymph
  Ogre/Ogre Mage (Ogrun take the place of ogres in the
  Iron Kingdoms)
  Orc (Orcs have been replaced by Trolls and the Farrow)
  Owlbear
  Pegasus
  Phantom Fungus
  Phase Spider
  Phasm
  Planetouched
  Pseudodragon
  Rakshasa
  Rast
  Ravid
  Roc
  Roper
  Rust Monster
  Sahuagin
  Salamander
  Satyr
  Shambling Mound
  Shocker Lizard
  Skum
  Slaad
  Sphinx
  Spider Eater
  Sprite
  Tarrasque
  Tendriculos
  Thoqqua
  Titan
  Tojanida
  Treant
  Triton
  Troglodyte
  Troll (the Iron Kingdoms has its own take on Trolls and
  their kin)
  Unicorn
  Vampire Spawn
  Winter Wolf
  Xill
  Xorn
  Yeth Hound
  Yrthak
  Yuan-Ti
  *Templates – Celestial Creature, Fiendish Creature,
  Half-Celestial, Half-Dragon, Half-Fiend, Lycanthrope,
  Vampire
  A Multitude of Monsters
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SOURCE: textdata/thevault/Iron Kingdoms/IK - A Multitude of Monstres.pdf