I tried writing a wiki article, but my topic wasn't deep enough to get to the full word count, and I couldn't think up a decent picture. Submitted it anyway, since something is better than nothing, and I'll pray for partial credit.
http://elementswiki.co.cc/articles/6663/Mechanics of creature cost
During the creation of any game, balance is a key issue. One such issue when creating the creatures for any Card Game is the cost / reward ratio. That is, what you pay for and what you get should be fairly consistent across the board. Strong creatures aren’t cheep, and weak ones aren’t expensive, as that wouldn’t make sense. After some research, some trends appeared, and appear to be some basic principles and rules behind why creatures cost what they do. This formula is not foolproof, as there are some holes in it, but for the most part it holds up.
The first part of this formula is the attack stat of the creature. As this is the primary offense of the game, it’s the foundation of this formula. Begin the calculation of the cost of the creature by giving it plus one quanta of cost for every point of attack it has. This is the end when it comes to most vanilla creatures. An abomination has five attack, so it costs five entropy quanta. A Devonian Dragon has ten attack, so it costs ten time quanta. Skeletons have just one, so they cost one death quanta. It’s pretty simple so far.
The next part that comes into play is the creature’s health. If a creature’s health is above five, add one quanta to its cost. If its health is above seven, add two quanta. If it’s ten or more, add three. There are two exceptions to this, Stone Dragon and Hematite Golem, but they are because of a rule that will come later. For example, an Ice Dragon has nine attack and six HP. Nine attack gives nine quanta, and six HP adds another one, making the final cost ten.
The main complication of this formula comes in the next section, which is its ability. Depending on a lot of factors, this can increase or decrease the cost. The ability can add up to four quanta to the cost, with some qualifications. Abilities that add one quanta to the cost are Gravity Pull, Infection, Vampire, Stone Form, Lobotomize, Lycanthropy, Evolve, and Phoenix’s rebirth. Abilities that add two to the cost are Devour, Paradox, Mutate, Poison, Dive, Heal, Immortality and the status effect, Devourer’s quanta drain passive effect, and Freeze. Hatch adds three quanta to the cost, and growth abilities are also worth three. A creature that can spawn other creatures adds four. Lastly, an ability that generates quanta adds one quanta of cost for each quanta generated. Firefly has one extra quanta of cost, but Rustler adds two. An ability that requires an element different from the creature’s type reduces the cost by one, as does an ability that sacrifices the creature, and starting with zero HP.
The last things, is that some elements give an innate bonus to creatures of their elements. These usually tie into the main theme of that element. All fire creatures get one cost-free point of attack. Life, Light, and Air all get a one quanta cost reduction to their creatures, and Earth gets one cost-free point of HP. With these calculations, the value of each portion of each card can be found. Likewise, when creating your own fan made card, keep these guidelines in mind.
Notes:
Entropy
Maxwell's Demon: 5 = 3 atk +2 (kill)
Abomination: 5 = 5 attack
Purple Dragon: 10 = 10 attack
Lycanthrope: 2 = 1 attack +2 (both stats buffed) -1 (duo ability)
Fallen Elf 4 = 3 attack +2 (Mutate) -1 (duo ability)
Death
Bone Dragon 10 = 10 attack
Virus 1 = 1 attack +1 (infection) -1 (sacrifice)
Flesh Spider 3 = 3 attack
Vulture 3 = 0 attack +3 (both stats grow)
Skeleton 1 = 1 attack
Mummy 4 = 5 attack -1 (duo ability)
Gravity
Sapphire Charger 5 = 4 attack +1 (momentum)
Armagio 5 = 1 attack +1 (grav pull) +3 (HP > 9)
Colossal Dragon 10 = 7 attack +3 (HP > 9)
Otyugh 4 = 0 attack +2 (kill) +3 (both stats grow)
Graviton Fire Eater 2 = 0 attack +3 (growing attack) -1 (duo ability)
Graviton Mercenary 4 = 3 attack
Earth
Antlion 2 = 2 attack
Hematite Golem 4 = 4 attack
Stone Dragon 10 = 8 attack +2 (HP > 7)
Graboid 3 = 2 attack +2 (attack buff) -1 (duo ability)
Shrieker 8 = 8 attack
Life
Emerald Dragon 10 = 10 attack +1 (HP > 5) -1 (Life bonus)
Horned Frog 2 = 3 attack -1 (Life bonus)
Rustler 1 = 1 attack +2 (quanta gen.) -1 (Life bonus) -1 (duo ability)
Cockatrice 3 = 4 attack -1 (Life bonus)
Forest Spirit 2 = 1 attack +3 (both stats grow) -1(duo ability) -1 (Life bonus)
Fire
Ash Eater 1 = 1 attack
Fire Spirit 2 = 0 attack +2 (growing attack)
Lava Golem 5 = 4 attack +3 (scaling both) -1 (duo ability)
Crimson Dragon 10 = 11 attack
Phoenix 7 = 6 attack +1 (rebirth)
Water
Chrysaora 1 = 0 attack +2 (poison) -1 (duo ability)
Blue Crawler 3 = 3 attack
Arctic Squid 3 = 1 attack +2 (freeze)
Ice Dragon 10 = 9 attack +1 (HP > 5)
Toadfish 5 = 5 attack +1 (infection) -1 (duo ability)
Mind Flayer 2 = 2 attack +1 (lobo) -1 (duo ability)
Light
Photon 0 = 1 attack -1 (element)
Golden Dragon 12 = 10 attack +3 (HP > 9) -1 (Light Bonus)
Pegasus 4 = 3 attack +2 (dive) -1 (Light Bonus) -1 (duo ability)
Guardian Angel 3 = 1 attack +2 (heal) +1 (HP > 5) -1 (Light Bonus)
Air
Dragonfly 1 = 1 attack -1 (Air Bonus)
Wyrm 4 = 3 attack +2 (dive) -1 (Air Bonus)
Azure Dragon 10 = 9 attack +1 (HP > 5) -1 (Air Bonus)
Firefly Queen 7 = 3 attack +4 (Spawns creatures) +2 (HP > 5) -1 (duo ability) -1 (Air Bonus)
Firefly 3 = 3 attack +1 (quanta gen.) -1 (Air Bonus)
Time
Deja Vu 1 = 1 attack
Devonian Dragon 10 = 10 attack
Fate Egg 3 = 0 attack +3 (hatch)
Anubis 8 = 5 attack +2 (quint) +2 (HP > 7) -1 (duo ability)
Pharaoh 9 = 3 attack +4 (Spawns creatures) +2 (HP > 7)
Scarab 2 = 2 attack +2 (kill) -1 (variable HP) -1 (duo ability)
Darkness
Black Dragon 10 = 10 attack
Devourer 2 = 0 attack +2 (quanta drain)
Parasite 2 = 1 attack +1 (infection)
Minor Vampire 3 = 2 attack +1 (Vampire)
Gargoyle 5 = 5 attack +1 (HP buff) -1 (duo)
Aether
Spark 0 = 3 attack -3 (0 HP)
Immortal 6 = 4 attack +2 (Immortal)
Phase Dragon 13 = 8 attack +2 (Immortal) +1 (HP > 5)
Phase Spider 3 = 4 attack
