Gathering Reasons:
Winning Streak which only needs two wins;
Cost 20 Electrums to be played, win about 200 when you win, repaying 10 lost games (and is about 480 when you win with an EM);
Skips won't make you lose time, and playing only against decks you have a pretty good chance to win against should let you get a Special Spin which values, money-wise, around 1300 Electrums.
Gathering Deck's Needs:
[It mustn't have upgraded cards (I'm still deciding on rares, probably not shards);]
Has to have at least an 80% Win Rate against the deck(s) it wins against;
The deck(s) it wins against must be some of the usually posted in Platinum;
Preferably, has to EM;
Prefarbly, a 500 HP deck;
Doesn't need to be a fast deck, it can even win via deckout;
Preferably, has to be small in order to draw into key cards faster (if it is a stall, it still is preferred a 30-cards deck but with Eternities to loop a creature);
The more the deck it counters, the better.
Gathering Decks usually posted in Arena (not caring about metagames):
Pestal;
Poison Rush;
SoSacPoison;
SoFree-MonoAir;
Swallow;
Dischole;
Ghostmare;
Earthquake Denial;
MonoAether (with and without SoW);
SN-based Decks;
? (pretty sure I forgot some important ones).
Gathering Counter Cards to said Decks (respectively):
Rainbow Decks;
Purifies;
Purifies;
Denial for quanta and destroying SoFrees (SoSac with shards);
Return Times and Eternity;
Sanctuary (maybe with Enchant Artifact);
Time Deck (in order to summon the Ghosts of the Past nightmare'd);
Enchant Artifact;
Steals for Dim Shields or Momentum Rush or Poison Rush for SoW-less MonoAether, Reflective Shield or Emerald Shield (the latter may be played with a lot of Heal so that it can survive to creatures who didn't get SoW) for SoWMonoAether;
Black Hole;
?.
Deck Ideas:
Enchanted Dissipation Shield: with Enchant Artifact we defend ourselves from Earthquakes and SoFo's destruction. A lot of Amethyst pillars should be able to give enough fuel to Dissipation Shields. May splash in 3 Time Pillars, 2 Eternities and 1 Gnome Rider to get a smaller deck in order to draw more consistently Dissipation Shields and Enchant Artifacts.
Another build may be with Time and Amethyst pillars, some draw cards from Time Quanta and Enchant Artifacts splashed from the mark.
Pros: if it gets going, almost nothing can stop you. It being a Duo with a lot of quanta generation means it doesn't fear Black Holes, and if we get a Dissipation Shield to work, it protects us from Discord's Scramble.
Cons: (don't know whether the AI knows that keeping SoP a little more may kill my Dissipation Shield in a blow without me having the time to regenerate the quanta needed for them). Needs a lot of Amethyst pillars, but not too many in order to not increase the deck size by too much. Dissipation Shields can be killed in a blow. Fears Momentum. Poison gets through. Spell Damage gets through. Something else I may have forgotten.
Decks to be played against: Dischole, Earthquake Denial, Pestal (not sure, but most likely won't have enough damage to kill the shield if it can drain a lt of quanta and viceversa).
Decks to Skip: Poison Decks, decks with an high damage factor (which should, I think, easily surpass 70 damage per turn).
Decks to Try: Aether, unless you play against them you won't know if it is a SoW-less MonoAether. If it doesn't have neither Psions nor SoW, it will be a win.
I'm pretty sure I forgot a couple of points in the deck needs and a lot of decks in the most common decks of the Arena. May have fogotten a couple of nice counters, too. In deckk Ideas I only wrote the first deck that jumped to my mind, haven't worked on that, yet.