Here's a fun list of REAL Elemental creatures I've been compiling over the years. The Fire Birds were the final part to complete this list. I've heard stories of birds dropping burning twigs before, but apparently in Australia, 3, YES THREE kinds of birds actively use/spread fire to hunt! Fire Bird info I got from a video on Casual Geographic (Hood Nature)

Electric:
Electric Eel
Oriental Hornet (It's stripes are Solar panels that generate electricity)
Ballooning Spiders (use their threads to fly on electric currents in the air)
Echidna (sense not emit. This is Knuckles' Emerald radar in Sonic Adventure 2)
Electric Stingray
Electric Catfish
Sharks (Sense not emit, Ampullae of Lorenzini pores around snout.)
Plant Pollen (Has static charge, that's how it sticks to Bees)

Fire:
Black Kite (carry burning twigs around to spread fire)
Whistling Kite (carry burning twigs around to spread fire)
Brown Falcon (carry burning twigs around to spread fire)

Heat:
Bombadier Beetle (shoots boiling acid)
Japanese Honeybee (swarms enemy and generates body heat to cook)
Pistol Shrimp (can do real Kamehameha/Hadoken)
Mantis Shrimp (can do real Kamehameha/Hadoken)

Water: (USE water, not listing everything that just lives in water)
Archerfish (Spit water at prey outside the water, can compensate aim for light bent by water surface)
Walrus (Gush water at the seafloor to hunt)
Whales
Dolphins
Octopus/Squid

Ice:
Pseudomonas Syringae (Creates ice, can freeze water above 0C)

Metal:
Scaly-foot Snail (Iron shell)
Eucalyptus trees (absorb Gold into their cellular structure)
Various plants (absorb metals into their cellular structure)

Light:
Fireflies
Angler Fish
Flashlight Fish
Bioluminescent Plants
Bioluminescent Fungi
Bioluminescent Bacteria/microbes
Octopus/Squid (Some use their chameleon skin to make light)
Tons of deep ocean creatures communicate by producing light

Dark or Ghost:
Assassin bugs (wear corpses as disguises)
Cordycep (parasitic Zombie fungus)
Parasitic Worm (snail eyestalk zombie infection)
Toxoplasma Gondii (reduces host's fear of danger/risks)

Poison:
Maned Rat/African Crested Rat (Lophiomys imhausi) (Rubs poison from plants into specialized stripes of hairs)
Hooded Pitohui
Ifrita
Rufous Shriketrush
African Spur Winged Goose
European Quail
Hoopoes
Ruffed Grouse
Bronzewing Pidgeon
Red Warbler
Various Reptiles
Various Amphibians
Various Fish, and Aquatic Animals
Various Arthropods (Insects, Arachnids, Crustaceans)
Various Plants
Various Fungi

Ka-Tra