I realize that like none of the content is in yet. But since all we've seen are Giant Spiders, Trolls and Dragons and don't know what is coming I thought I might throw out some suggestions.

First off, I'd like to see the ability to make world monsters stick to the correct environment and not roam the whole world. Would Giant Spiders really just randomly traverse the entire continent at high speed? Seems like very un-spider like behavior to me for a critter that normally lays in wait. So it would be thematically appropriate if certain monsters could restrict themselves to big forests, near mountains, snowy areas, deserts, etc.

Galciv inspired monsters:

• Giant Squirrels - Pure Evil. Random early game low level monster.
  
• Automatons - (Early Proto-Yor). Golem like creatures that are forged from metal and fire. Potentially might offer themselves as mercenaries or heros to Fallen Channelers but never to humans.
• Mind Breakers - Iconians captured by the Dread Lords, experimented on and twisted. The few survivors in the world had escaped the Dread Lords and hid in the deep dungeons of the world. They're experts with magical artifacts and mind control, but these warped individuals have been mentally broken and now create vast underground dungeons to protect themselves (high level creatures). A sympathetic enough Kingdom might attract one it its war against the Fallen as the Mind Breakers still want vengeance against all those who served the Dread Lords.
  
• Giant bugs - Kudos if they have dark religious tendencies.Make them Giant Ants and it becomes a tribute to at least 3 games

Fantasy inspired monsters:

• Froggies - Spear wielding Amphibians that attack from the sea
• Shadow Hounds - Plains roaming low level monsters
• Nightmare - Originally a creature created for the Dread Lords to show off their dominance of other creatures. This flying creature of fire and earth can potentially be bound to Fallen Channelers as a flying mount.
• Pegasus - Strange winged horse. High level creature like the nightmare can be bound by Human Channelers to become a flying mount.
• Elementals - Mid-Level monsters that can spawn from the Elemental Shards. Immune to non-magic weapons and bypass non-magical armor.
  
• Sea Serpents, Giant Squid, Sead Dragons - High level monsters that make it unsafe to build a vast armada of ships. It just isn't safe out on the deep open ocean.
  
• Water Horse - These roam up and down rivers making it dangerous to cross. Mid level monster.
• Giant Polar Bears - Low level arctic monster. Big enough to eat a man in a single bite.
• Wraiths - High Level monsters. The Ghosts of Dread Lords who lost their civil war badly and weren't allowed to die.
• Zombies - Low level monster. Ah, the things that can be made with Death Magic. Summonable
• Witch/Warlock - Low Level monster. A lesser Death Magic user who didn't have the ability to channel.
• Titans - Colossal Humanoids the Dread Lords created to do their manual labor. A few still remain in homes they've claimed. High level.