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.
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.