By Bryant Durrell (Dangerous Experiment), David Eber (Ascended Speed, Inauspicious Reburial, Architect Recycler), and Matthew Gagan (Killing Rain).
While Shadowfist is a bit young to have the same rich vocabulary of deck types one sees in Magic, its loyal fans are beginning to build a stable of deck strategies. The deck types below are a start at a taxonomy of such strategies; as more arise, more will be added. My thanks to the authors for their contributions.
Ascended speed decks take advantage of the Ascended's ability to build up a large army of characters, usually weenies, in a very short time. This is usually done through a combination of cost reducing sites (Proving Ground and Family Estate) and the infamous Mole Network, which steals a point of power from your opponent's pool. What makes the Mole Network so nasty is that if you go first you can steal your opponent's only point of power before he can play, slowing him down while simaltaneously speeding yourself up. Even without it, the deck will pump out a large number of creatures early, cycling through the deck at a rapid pace. The zero cost Operation Killdeer and Covert Operation is often included in these decks, as are Shadowy Mentors in case the opponent does manage to play something substantial. Finally, Explosives and Grenade Launchers are there to take advantage of both the lack of early defenders and the Stealth ability that is common to the Ascended. This deck tends to win quickly. Decks that can make a strong comeback are useful for dealing with this deck, as is Final Brawl, Mark of Fire, and Cave Network.
The Inauspicious Reburial deck revolves around keeping your opponent from playing by eliminating his resources. To this end, cards which cause discards (Curtain of Fullness, Arcanowave Researcher) and cards which toast resources in play (Abyssmal Absorber, Disintegrator Ray) are commonly used, as are cards which wipe out characters (Nerve Gas, Neutron Bomb, White Disciple). Of course, the Inauspicious Reburial is the centerpiece of the deck. Anyone who has played Magic and has been on the recieving end of a Hand or Land Destruction deck will know how it feels to have one of these work against you. You have to work hard to keep your resources in play. Confucian stability is standard, but the discard effects make them hard to hold. Cards that counter discarding (Resistance Squad) are a start. A better defense, I think, are fast decks which keep a lot of resources in play and which keep up the pressure on the opponent. Foundation sites work well too, and mono-faction decks are less vulnerable to this sort of thing.
And finally, there's the Architect recycler deck. This deck takes advantage of the Reinvigoration Process edge to the fullest, allowing the player to constantly recycle his forces. Arcanotechnians are often used as well. A typical combo in this kind of deck is the Vivisector/Neutron Bomb, which allows you to grab power, kill everything in play, and then drop out a big guy and hit an opponent's site. Helix Rethread is also common in this deck, as is the Arcanowave Reinforcer. This deck relies on the Reinvigoration Process, so if you can eliminate all of them you will hurt it badly (Thunder on Thunder after the Neutron Bomb). This deck is also vulnerable to Inauspicious Reburial decks as well.
In the Killing Rain deck, five Auspicious Termites and five Killing Rains are the core. Other cards can and do sometimes include Mark of Fire; Burn, Baby, Burn; Scroll of Incantation; Stone Gardens; Inner Sanctums; Gnarled Marauders; Walkers of the Purple Twilight; Inexorable Corruption; and The Rackets. You damage sites throughout the game, the Termites come back to you, and you use the Rackets to gain a power edge over your opponents. Ideally, none of them will be able to mount much of an offensive, because no one ever has much power. In some play groups, this deck is an effective standard. It's best fought with Securities, Auspicious Termites of your own, and most particularly with Dark Travellers.
The key to the Dangerous Experiment deck is the insight that it doesn't matter if your opponent can toast a card when there's no card for him to toast. Jose Garcia invented the recursive strategy that's key to making Dangerous Experiments, well, dangerous when he combined it with Guiding Hand card recycling methods to enable up to five or six Dangerous Experiments per turn. Other cards are Vivisectors (to get the resources out quicker; play the Vivisector and have it sacrifice itself immediately), Architect thugs (you'll have the resources and the power), and perhaps Reinvigoration Processes. To play the deck, simply build up resources and hold Dangerous Experiments until you're ready to burst out with Experiments, Into The Lights, and Wind Over The Mountains.
Hackers make this deck a lot easier to fight than it was pre-Flashpoint. Confucian Stability can also hurt. A common mistake is to generate all the power and then find oneself without the ability to do anything with it; there's frequently a turn or two after the Experiments go off in which you can try and build a cushion of advantage before the thugs show up.
There are numerous enhancements to this deck, but in the interests of encouraging diversity I'll leave people to experiment (pun intended). Shay Bockmann has written a guide to Dangerous Experiment decks that may be of interest. Be aware that the Players Guide will include an important errata to Dangerous Experiment that may make it less useful in this type of deck.