Inhabitants of Yekub

The worm-like Yekubians send special cubes out into space, and if an intelligent creature finds and looks into the cube, their mind is switched with the Yekubian's for a brief time.  

Vile Fungus

The Vile Fungus appears to be a mass of regular mushrooms from a glance, yet they can cast out tendrils that can infect those they touch. The victim is then progressively overcome by the fungus until they are unable to move and the cycle starts over.

Typhonian Beasts

Typhonian Beasts are avatars of the Egyptian god Set, and can take the form of a jackal-like beast, or human with the beast's head.

Tree-Men of M'bwa

Once human, the Tree-Men of M'bwa become fixed in place and slowly turn into a human-shaped tree.

Travelers

Much like the Shan, Travelers invade a host's brain and take control of them. Unlike the Shan, however, Travelers are physical beings, and enter their victim's body through their mouth. They start off in a larval form (shown below) and mature once inside the host. Unlike the Shan, however, Travelers can't easily vacate their host.

Shugoran

The Shugoran race look like smaller versions of Nyarlathotep's Shugoran form. They are amphibious and have black, catfish-like hides, with small wings—or fins—and long proboscises.

Seekers

Seekers are agents of the Adumbrali. They appear as unusually perfect humans.

Reptile People

Reptilian quadrupeds that predated the arrival of man, the Reptile People are now extinct, though their bodies are perfectly preserved within the catacombs of Irem, City of Pillars.

Rat People

Once human, Rat People have degenerated to a near animal state. I get the impression from their write-up in the old Malleus Monstrorum that they are even less human than those pictured below, as it says that they sometimes walk on all fours and has no mention of weapons or even clothing.

Spawn of Othuyeg

The Spawn of Othuyeg are simply smaller versions of their sire, meaning they are a mass of white tentacles surrounding a single eye... so basically a white version of Cyaegha (hence the usurped image).

Minions of Othuum

Minions of Othuum are yet another "heap of twisting, ropey tentacles". It's become pretty clear to me that peoples' association of Lovecraft and tentacles didn't actually originate from his writings at all, but instead, those that came after him.

Gyaa-Yothn

Gyaa-Yothn are said to be related to—and are possibly just domesticated—Ghasts, though they have a horn protruding from their head and are covered in fur. They are ridden by the people of K'n-yan, as well as being used as beasts of burden.

Children of the Green God

Plain and simple, the Children of the Green God are rabbit-people. They are covered in coarse hair, have elongated ears, large eyes, sharp rodent-like teeth, move in a hopping gait, and dwell in underground warrens. There's not much else to say really. So that means that in Call of Cthulhu there are Serpent People, Reptile People, Rat People, Fish People, Pig People, Insect People, Goat People, and also Rabbit People. Who knew the Mythos had so many anthropomorphic animals?

Gn’icht’Tyaacht

The Gn’icht’Tyaacht are tree spirits native to the jungles of West Africa, and are only able to leave their Nuwanda Trees at night. They are seven-foot tall, lanky humanoids with long pointed heads. They also have huge claws and prominent, sharply pointed teeth.

Dark Ones

I'm a little confused as to the description of the Dark Ones. Their entry says they are parasites that only live inside reanimated corpses, but then it also says they are a race of "dwarfs", which doesn't make any sense. Regardless, they are known for creating magical artifacts. Perhaps "dwarfs" was in quotes simply because dwarfs are known for forging weapons and such.

Children of the Wind

The Children of the Wind are bloated, corpse-like monstrosities, with stumps for limbs. They are always accompanied by howling, gale-force winds.

Alskali

Alskali are about ten feet tall with squat, heavily-muscled bodies. They are hairless, with dead-grey skin and huge hands and feet. Each has a single black glossy eye in the centre of their otherwise humanoid faces. These giants have entered into human folklore as the Cyclops.

Aihais

Aihais live on Mars, coexisting in an uneasy truce with the Martians. They live underground in hidden cities, where most of them worship the Great Old One, Vulthoom. Those that do, live out 1000-year cycles of hibernation and waking. The Aihais are generally a peaceful people.

Adumbrali

The Adumbrali are a race of two-dimensional, shadow-like entities that dwell in an abyssal dimension. They are only capable of moving in the horizontal plane and cannot move vertically, even in their own dimension, though some have the ability to teleport and reorient themselves to a different plane.