Just to suggest a few options here; the deck that caused MrBlonde the most trouble I think was a simple Fractal/Recluse rush; don't underestimate the deck. Tweaked with say a Bond or two and you have a powerful combo.
Light: Light has powerful creatures; Archangel should not be underestimated, especially a Rage/Angel deck. The Dragon and the Nymph are also heavy hitters; best is some other form of creature control. Possibly a Gravity Shield or Mutation? Also dangerous is a Fractal/Hope deck. The RoL are extremely vulnerable but expendable; 1 extra point of protection as well as damage to the opponent and another Light quanta to boot for the price of free is one of the best deals in the game. Plague or RoF can fix this, but expect for them to recover quickly.
Darkness: Darkness will be interesting. I suggest a straight Recluse rush, or a deck with PA. Steal is honestly one of Darkness's best weapons; their creatures aren't that strong. However, a Fractal/Pest deck could cause troubles; mass creature control (or a few Otys) can take care of this. Don't underestimate Darkness' healing abilities as well. Vampires, Drain Shadows, and even Antimatters (see Entropy) can make Darkness very dangerous to deal with.
Life: Creature spam w/ Adrenaline. Bone Wall will be useless 9 times out of 10, but expect to see Jade Shields as the Thorn Shield can only help Death Decks if played poorly. My best successes against Life decks use their low HP against them; Otys are my weapon of choice IF you can get one out in time. Jade Dragons will defy this strategy, but those are not nearly as common as Frogs and Cockatrices. Spirits can be handled as well.
Water: Water is interesting. Water decks can lean towards control, but don't expect to see Flood, and poison is not nearly as effective as anything else. I suggest Mummies or Recluses. However, mixed with heavy permanent control can mess this strategy up. Butterfly Effect or Steal can both remove a pesky Permafrost Shield, and few of Water's creatures are particularly strong. Also, a Fire Shield and Skellie rush IF THEIR SHIELDS CAN BE REMOVED will work.
Fire: Fire will likely be some sort of rush deck; rarely will anyone try to stall out except for a Lance deck. A Mirror or preferably Jade Shield will remove this threat. Also notable is Fire's lack of creature health; even an unupped Oty can cause quite a bit of harm. On the flip side, they might be the strongest deck in terms of direct creature control however. RoF, Lances, Fire Shield, Rage Potion, and possibly others can wreck carefully constructed plans.
Earth: Shrieker rush. I think a Water/Death hybrid would work best; a standard speed poison with Permafrost Shield and Congeal to slow things down, and Chryasoaras to poison. Also an Earth/Gravity control deck can be deadly. The answer is likely the same; try and poison them out, possibly with flying Arsenics?
Gravity: Dangerous, especially since someone's guaranteed to pair it with Earth and Entropy. Discord is deadly; sticking with mono is dangerous but so is anything else short of a full-blown rainbow deck. Steals or other permanent control can help, but thats only half the problem. Gravity can use Armagios as "health packs" and Momentum as a weak form of permanent control, rendering shields useless. Also is the ubiquitous Otyugh, one of my personal favorites. There's really no way to get around a well setup Oty, as a pure Oty deck will almost certainly have Blessings/HA/Chaos Power and/or other protection. Boneyards and Bonewalls can make it interesting however.
Time: No one's gonna be stupid enough to rewind a Mummy, and if they are, pack a Gravity Mark to ensure if anyone makes that mistake it will be costly, or at least bluff them into thinking so. Time's cards are not that cheap; a Discord and Butterfly Effect deck with Mummies might very well be interesting to counter with, with Novas fueling the Gravity and Time... Against PuppyChow's speed Time deck there is almost no chance however, without a specially prepared deck with Phase Shields, Bone Walls, and Sundials. Don't underestimate that rush.
Aether: Aether has the old Mono-Aether archetype, as well as Fractal. While they don't work together, the two are very dangerous enough. Against a Mono-Aether with Immortals or Phase Dragons, a shield deck, possibly Death/Earth could really mess them up; Diamond to make attacks far less effective and Earthquakes to remove their quanta slowing them down further. However, ALWAYS pack more than 30 cards in such a case; they will likely have 30 or 31 for maximum speed, and 6 Phase Shields can and will ruin someone's day if they aren't neutralized or out-lasted. A Fractal deck is a completely different beast; any number of variations persist. Fractal/Pest has weak health and damage potential (at least until late game) but near complete quanta control. Fractal/Frog is a great rush deck (as is Fractal/Recluse!), and a Fractal/Hope deck can absolutely dominate if setup properly. Any number of variations can work, and often will (Fractal/Minor Vampire, anyone?). Mass creature control or negating their advantages is the best bet to win; once again a good shield might save the game.
Entropy: Entropy's my worst element, I'll straight up admit it. What makes it so strong and weak is its unpredictability; if they can get an Improved Mutation factory working the game becomes highly volatile. Likely a Mono-Entropy won't be played; while Abominations and Micro Abominations hurt, they have almost no other damaging creatures. Antimatter can cause quite a problem, but a growth or scavenger based deck can survive. Antimatter/Liquid Shadow has the potential to be dangerous however; it completely turns a creature against its owner by damaging him/her and healing the opponent. Rewind might actually be the best defense against that; the second playing cost is almost worth them losing two cards.
Last thought: Pay attention to the writeups of the Master's matches. The decks used in those battles, especially the latter battles of each Master are good indicators of what will be seen in this War here, as most of the Masters, old and new are involved, and simply because they showcased what works and what really doesn't. I'm sure there's plenty buried in there that I missed here, and I think ATM they are possibly the best indicators of whats to come.
