I had to get a little creative with how I interpreted some of the categories, since the categories weren't really designed for this, but hopefully I'm capturing the spirit of what they represent.
Anyway, I'm pretty happy with how these turned out. Marvel, DC, if you're reading hmu ;)!
Semi-intelligent humanoid: Living Ghosts (49)
Undead: Sinister (80)
Ancient Fey: Flash (28)
Giant/Ogre/Troll: Bane (9)
Great Wyrm / Lizard: Despero (24)
Aerial: Torchborn (95)
Lurks in the Water: Penguin-Folk (70)
Extradimensional: Jeanists and Genoans (47)
Mythological: Dark Knight (21)
Foul Crawly Underworld Thing: Faceless (26) (Play on words, this is more the "seedy noir underworld" than a literal underworld :p)
Humanity may be gone, but they've left behind their legacy, the Torchborn; human-like warforged covered in flame who take to the skies like jets of light. They have developed an alliance with the Genoans, indigo-blue dwarven refugees from the Denim Dimension who settled onto this world after the fall of their own civilization under circumstances recorded only in legend. The Jeanists, the highest denim-smiths of the Genoans, have created a super-denim capable of withstanding and containing the flames of the Torchborn, allowing them to build a new civilization. They also wear the jeanist containment suits symbolically, as atonement for the responsibility they feel for their role in the fall of humanity. The Denim Alliance are guided by the Flash, angelic creatures manifesting from the Speed Force, who use their supernatural speed to facilitate a high-speed communication network along the denim roads.
Despite their "Denim Road" network and powerful abilities, the Denim Alliance faces many threats. The Torchborn are vulnerable in the water, even with the most water-resistant jeanist containment suits, and the Penguin-folk are indomitably nefarious. The Penguin-folk have formed a Bile Axis with the Banes, monstrous ogre magi whose veins pulse with powerful venom, who are as cunning as they are strong, and their "survival of the fittest" libertarian beliefs run counter to the ideals of the socialist democracy of the Denim Alliance.
The Sinister stand alone. A living neural network of a species, each pale-skinned undead humanoid with an iconic red gem on their forehead acts as an independent thinker, yet is also consciously aware of its role as part of a larger system; a larger, distributed intelligence. They appear mostly content to develop from within, only occasionally extending their borders, in slow and careful iterations. But their borders are expanding, without fail. When encountered on the battlefield, their soldiers dress in black armor, bat-like helmets, waving their flag with the symbol of a bat. It is said that the Sinister Intelligence is in fact the Dark Knight, a demigod-like force from a war outside of spacetime known as the Fourth World, precariously balanced between justice and vengeance.
There are two information-brokering factions who operate independently of any other organization. The Living Ghosts, uncanny humanoids capable of invisibility and intangibility, and with knowledge of advanced techno-magics, are often summoned from their mysterious realm as assassins and saboteurs, although their price is high and often the buyer receives more than what they bargained for. It is rumored that the Living Ghosts were created by Darkseid himself, perhaps to keep tabs on the Dark Knight as part of his Black Glove. The Faceless come from a netherworld, another magical plane. They are a spiritual and obsessive species with the ability to mimic any face, but lack faces of their own. They can often be found in more densely populated cities working as private investigators, although some have taken up the cause of The Sacred Order of Saint Dumas and serve the Sinister.
However, with the arrival of the Flame of Py'Tar from the celestial beyond, the three-eyed psycho-dragons known as Despero, former alliances and enemies are being challenged. Their psycho-flames burn the earth and corrupt the Torchborn, enticing them with power, only to dominate their will. Even the Sinister appear vulnerable to the psycho-flames, and some Sinister have been severed from the system-intelligence. If the Denim Alliance, the Bile Axis, and the Sinister hope to survive, they must come together to force the Despero from whence they came.
Semi-intelligent humanoid: Collosi (17)
Undead: Frozen (30)
Ancient Fey: Green Goblins (35)
Giant/Ogre/Troll: Grundies (40)
Great Wyrm / Lizard: Annihilus (4)
Aerial: Robins (75)
Lurks in the Water: Starro (86)
Extradimensional: Plex (72)
Mythological: Templars of the Green Lantern (91)
Foul Crawly Underworld Thing: Symbiotes (89)
In this world of gods and monsters, humanity cannot survive alone. Most humans have developed symbiotic relationships with other organisms, sometimes socially, sometimes biologically, sometimes amicably, and sometimes not so amicably.
To the north are the Frozen, cryogenically frozen undead wights, dominated by the Lich King Fries, who wishes to destroy all emotion. They are held at bay by the Starro, a race of deep ocean (and deep space) psionic starfish-like creatures. They have brokered an alliance with the Templars of the Green Lantern, wielders of the holy green light. With the consent of the Templars of the Green Lantern, the Starro have mind-controlled the human tribes of the Northern Pole, creating a hybrid psionic super-force against the Frozen. The Starros' long-term motivations, however, are unclear.
In the southern jungles, humanity has entered an alliance with the Robins, tengu-creatures who soar above the jungle, scouting for rogue Grundies, monstrous corrupted jungle elementals that threaten the human tribes. In this region, the human / robin alliance is led by the Supreme Intelligence and its council, an extradimensional, slime-like intelligence that hybridizes with other species, turning them into blue-skinned, white-haired supermen. They work to build a cosmic, psychedelic, techno-utopian jungle civilization. The council members, known as the Plex, are treated as divine nobility.
In the western plains, there has been an incursion from the Negative Zone, an underworld like an inversion of reality. From the Negative Zone pours the Annihilation Wave, a hive species of cosmically-powered insectoids which threaten the entire world, spurring even the Frozen to consider a temporary truce with the Templars of the Green Lantern and the Starro. The effects of the negative zone have turned some humans into Collosi, super-strong metallic-skinned humans. Fortunately, the Collosi have thus far all been good-natured people who wish to be heroes in the fight against the annihilation wave. The Symbiotes, those who have merged with inky monsters leaking from the negative zone, are more ambivalent in their motivations, but have mostly served as a boon against the powerful Annihilation Wave.
The effects of the negative zone incursion have also reached the eastern mountains, where some of the technocratic goblins have begun to mutate into the cosmically-powered Green Goblins, hobgoblin-sized engineer-warriors who have begun to develop technology rivaling the Plex. At the moment they fight with the Templars of the Green Lantern against the Annihilation Wave, but neither the Plex nor the Starro will have anything to do with them.
Semi-intelligent humanoid: Grimmlins (38)
Undead: Noumu (64)
Ancient Fey: Key-Men (48)
Giant/Ogre/Troll: Hulks (43)
Great Wyrm / Lizard: Black Mistlings (11)
Aerial: Angels (3)
Lurks in the Water: Pinkies (71)
Extradimensional: The Fog and Danny the Street (92)
Mythological: Wonder Women (99)
Foul Crawly Underworld Thing: Ferals (27)
A world trapped in a liminal metaphysical state; rather than day and night, it passes through dream and nightmare. In dream, The Fog rolls through like rainbows and cotton candy. Everything is connected by Danny the Street, the consciousness that makes all travels short and sweet and always leads to where you want to go. In nightmare, the Black Mist consumes, a negative-space like fire consuming film from the edges and spots from within. Nothing is connected, consciousness is fleeting, things disappear, are forgotten, never were.
All things are subject to dream and nightmare, except the Key-Men. Gray-skinned fey whose ten "psycho-chemicals" super-senses allow them to see through the metaphysical barriers and "unlock" alternate physical and metaphysical planes. Unfortunately, they seem content to play tricks and cause a little mayhem, rather than use their abilities for anything good.
The Wonder Women, divine demi-god clay golems created by the gods, live safely on their island of Themyscera, immune to the effects of The Fog and the Black Mist so long as they stay on their island, protected by a network of golden lassos of truth. They arrived from the stars on cosmic rays sent by the gods, although some were corrupted upon arrival, mutating into males known as Grimmlins, large brutes of cracked rock. However, even this may have been the gods' plan, as the Grimmlins, for all their brash and ill-temperedness, are often the only protection against the Hulks, green-skinned monstrosities even more violent and powerful than the Grimmlins, who exist only to SMASH!
In this liminal world, humans take several forms. There are the aforementioned Hulks, who embody the frustrations and impotent masculine rage of humanity. Then there are the Angels, winged humans whose civilization is like a techno-magical baroque painting come to life. They utilize a divine metal known as Nth metal to power their constructs, and the Archangel elite lace Nth metal flachette-feathers in their wings, carry Nth metal maces, and wear lightweight Nth metal armor. Whereas the angels reflect austerity, propriety, and the seriousness of humanity, the pinkies live in the Octopus Gardens in the Shade, reveling in fun and lightheartedness. They are pink-haired, lilac-skinned, fuzzy-headed humanoids with cute satyr horns, black eyes and gold irises, who secrete their acidic fluids in spurts of fun and whimsy. The Ferals are druidic beast-men who live in the Dark Forests, and live more like animals than humans. For as dangerous as they are, with their supersenses, superhuman physical abilities, regeneration, and claws, for as much as the Angels like to paint them as boogie-men, the Ferals are generally not interested in hurting anyone, and merely wish to be left alone and to do what they must to survive. However, the pretense of their threat has led to Ferals being captured and experimented on by Angels, having "cold-iron" adamantium implanted into their skeletons, and thaumaturgically-willed into supersoldiers.
Finally there are the Noumu; vantablack bird-like tengu-humans with sharp teeth lining their sharper beak, their near-empty brains exposed to the world. They exist in a state of True Neutral, but were alchemically manipulated by some Dark Lord long ago into beings of pure destruction, like Null Elementals. The Hulks may destroy, but their rage comes from emotionality and feelings of inadequacy, whereas the Noumu destroy for No sake. The leader of the Noumu is the High Noumu, a rare being with human-like intelligence that has ascended to a nirvana-like state of detachment from the material plane. It is said that the High Noumu's right-hand agent is a Black Mistling, a child of the Black Mist itself. It appears as a vaguely humanoid, black and purple fiery essence, and appears to have teleportation abilities, but it is said that the Black Mistling holds significantly greater power, and is manipulating the High Noumu towards the aims of the Black Mist.