I don't know if this has already been done, but I took a crack at classifying all of the creatures in Elements. I think that new cards referring specifically to a "type" of creature could open up some new possibilities. I only wrote the unupgraded names, but they all carry over.
Please inform me if you think one belongs somewhere else, or if there is a better category that some fit in.
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Classifications
Insectoid - Antlion, Graboid, Flesh Spider, Deathstalker, Forest Scorpion, Ash Eater, Dragonfly, Firefly Queen, Firefly, Scarab, Dune Scorpion, Devourer, Parasite, Phase Spider
Humanoid - Gnome Rider, Hematite Golem, Lycanthrope, Fallen Elf, Mummy, Graviton Mercenary, Graviton Fire Eater, Lava Golem, Mind Flayer, Crusader, Anubis, Pharaoh, Gargoyle, Immortal
Beast - Shrieker, Maxwell's Demon, Abomination, Schrodinger's Cat, Skeleton, Sapphire Charger, Armagio, Otyugh, Chimera, Horned Frog, Forest Spirit, Fire Spirit, Chrysaora, Blue Crawler, Arctic Squid, Toadfish, Pegasus, Minor Vampire
Dragon - All dragons, Rustler, Wyrm
Divinity - All nymphs, Guardian Angel
Bird - Vulture, Cockatrice, Phoenix
Other - Virus, Steam Machine, Photon, Deja Vu, Fate Egg, Voodoo Doll, Spark