YouTube user Biblaridion, who normally covers language creation in world-building, has also created a playlist of videos featuring the step-by-step evolution of life on an unnamed, Earth-like world rich in hydrogen sulfide. The graphics are great. The concepts are plausible. Watch it here.

Preradkor is the creator of not one, but two worlds, planet Coatlique and planet Ullr. Coatlique is home to large animals reminding me simultaneously of mammals and arachnids, although some resemble sharks with whip-like jaws. Coatlique is hot, stormy, and irradiated, leading to a high level of mutation such that all animals and plants are chimeras. Ullr is much colder. It is home to the askewbugs, asymmetrical insectoid organisms. Check out his DeviantArt gallery.

Illuria is the name of a planet with its own wiki that anyone can edit. According to the introduction, it was discovered in 3018, has a 48-hour day, and a year that is 730 Earth-days long.

In addition to mountains, deserts, scrublands, savannahs, temperate forests, rainforests, marshes, and prairies, it has acid swamps and the “mineral sea,” a body of water rich in iron, gold, and silver. Its sub-biomes include rust reefs, crystal caves, and wiregrass meadows.

Among the animals of Illuria are crystal borers, shrimp-like, colonial animals that make nests out of crystals.

Among the plants of Illuria are crawling boom creepers, plants that grow rapidly at night on stored fuel, seeking out sleeping animals to infect with its spores, which it often delivers so explosively that the animal is killed.

As of this writing, the ecosystem is still incomplete. The life on the continents is undescribed. The gold shiners eat shellfish that have no page of their own. The hovizards lay their eggs on stilt plants with no page of their own. Visit and add your own ideas.

​There are many awesome artists on DeviantArt.com, but not all of them have well-defined exobiology projects. Some focus on the behaviors and outside appearance of long-extinct organisms on Earth. Some engage in all kinds of art and mix all their work together. Some post great alien pictures, but give no descriptions or environmental context. Some deal more in fantasy than science fiction. Some only had a few good ideas and then stopped. Some create strange landscapes covered in what might possibly be plants perhaps inspiring someone else to offer design and explanation. Here are those that at least deserve recognition as artists:

Demmmmy is the creator of Fentil, an Earth-like planet of higher gravity and thicker air. It is the flora of planet Fentil I am most enamored with. There are plants that grow at the top, creating gigantic basket-like structures. There are plants that breathe. There is good fauna, too. There are the complex skeletons of the Dystroma and the complex vascular systems of the Photonimals. They are both highly creative and surprisingly plausible.

​Salpfish1 is the creator of several worlds, including Tregama, home of swimming creatures with siphon-legs and the charybdis fish, which uses suction to create whirlpools and feed on anything on the water’s surface. He also creates a variety of future Earth animals, such as land anomalocarids, fish-like mollusks that eat anemones and then spit stinging cells at predators, and pigs that hunt like frogs. Another favorite of mine is the blind, flying, cave shrimp.

Concavenator is the creator of Horus, a world connected to Victorian-era Earth via wormhole. It is home to red plants with hearts, tube-jet fish, and large land vertebrates. The animals have a double spine. The dorsal spine runs from the skull along the back, while the ventral spine runs from the chest along the tail. They are connected by ribs. The tail houses the respiratory and sometimes reproductive organs. The land animals have six limbs. Some run on the hind limbs and use the forward limbs for grasping while the middle limbs are vestigial. Others stand on the front limbs while the rear four are used as wings. My favorite is the lazy animal that uses its front limbs to carry its head around while it grazes.

​Tapejara is the creator of not one, but six worlds, including Tunjera, Adam, Eve, Lyell-3, Toci-1, and Midgard. They are currently all unfinished but all have huge potential. The animals are very creative. Planet Adam is home to “fish” with large ventral “mouth-bodies” attached only by a narrow tube containing the esophagus. Planet Eve is home to completely armored creatures whose only openings (the mouth and anus) are both located in the head. Some are colonial. Toci-1 is home to animals with chain-link ribcages, helical muscles, and specialized organs capable of regenerating any damaged tissue anywhere in the body – as if all the stem cells were in one place.

Abiogenisis is a mind-blowingly good artist in general but especially of alien sea life. My favorites are the swordswallower, bushwacker, cloakmouth, and antlerworm. I hope these eventually get organized together in an Expedition-style book someday.

Avancna is the creator of planet Tlaquanaru. Although the map proves it is certainly not Earth, the animals are eerily similar to those of our world. There are what appear to be descendants of iguanas, birds, moths, and very many fish. My favorites are the rolling echinoderms and the rotifer-cephalopod-creatures that drop pom-poms full of ammonia to deter predators.

​Ramul is the creator of Red Earth, a planet about halfway between Earth and Mars in all its characteristics. It is home to a staggering number of octopod species, but my favorites are the worm grasses (plant-like animals), siltribbons (worms with long mouths that suck up muck), monolingulates (filter-feeding squid-things), and the era worms, which are known to hatch all at once and secrete a poison that kills everything around them.

Biofauna25 is the creator of not one, but two worlds, Epimethius and Odin. Either project has the potential to be a great book.

Epimethius is a larger, stormier version of Earth. There are at least four lineages of plants, including the ridge-leaves, the maze-roots, the feather plants, and the peeling plants. There are an incredible variety of radially-symmetrical animals, some resembling insects, crustaceans, mollusks, amphibians, and mammals. Variations on the theme include laterally flattened shrimp-like forms (making them bilaterally symmetrical) with their eyes on the back end. There are even more bilaterally-symmetrical animals. They have dual ribcages. The ventral ribs house the digestive organs and the dorsal ribs house the heart and respiratory organs. Many resemble fish and snakes. Others resemble deer or crocodiles. Some make silk, some retract their heads into hoods, and others have their simple mouths in the chest. My favorites are probably the frog-like potes.

Odin is a small, relatively dry planet largely covered by inedible sheddings of red plants floating in the air. Different species of floating plants receive energy from sunlight, lightning, or wind motion. They form wide nets to safely diffuse electrical discharges. There are three main groups of animals. The first has a four-stage life cycle, the second has a five-stage life cycle including a sessile phase that feeds the young with nectar, and the third has a five-stage life cycle like the others, but in reverse. I don’t know exactly how he organizes them into groups, but I estimate there must be at least twenty-seven orders.

Juniorwoodchuck is the creator of Aurora, planet with long days and animals which spend one life stage as a plant. He also speculates about future Earth life, my favorite examples of which are the turtles that swim with their necks and the squid-moles.

​Snaiad is an exobiology project created by C. M. Koseman. The planet Snaiad is inhabited by many creatures, of which the vertebrate phyla are described on the website. These animals have hydrocarbon bones, hydraulic muscles, endocrine-based cognition (as opposed to neural), and two heads. The lower heads are mostly boneless and used for eating. The upper heads are actually heavily modified genitals used for defense and covered in sensory organs. There has been talk of turning it all into a book. I really hope this happens, but only if the invertebrates, plants, and microbes are also described.

Planet Epona is a dying world with only periodic volcanism. It is during these short bursts of ten million years or less that life flourishes and diversifies. Otherwise, it survives only in the seas where it can barely scrounge up enough carbon to grow. There are several lineages of plant and animal life, including bubbleweed, tiered seaweeds, pentapods, bivalve ambush predators, and colonial flying insectoids. The pentapods and tiered land plants make use of bone-muscles that expand rather than contract. They have variable metabolisms based on interesting biochemistry. While the project seems to have stalled, it can always be revived and in any case is worth the read.

Artist Emily Holland is writing a trilogy about a human expedition to the planet Ilion, a tidally-locked planet of mobile red plants and colonial ambush predators. Sunrise On Ilion is her official website where you can watch the project as it unfolds. She covers the geography, climate, geology, and especially the biology of this fascinating planet. You can also follow her on her DeviantArt page.

Gert van Dijk and Sigmund Nastrazzurro create the Planet Furaha website (also known as Phoenicis 4), detailing the astronomy, climate, geography, and biology. There are maps of various projections and many animations showing the complex way the animals walk, swim, and fly. There are radially-symmetrical animals and bilaterally-symmetrical animals. There are also interesting plants. There are anecdotes from the lives of the biologists living there. I really hope it turns into a book. Sigmund also writes a separate blog on graphic design and speculative biology in general.