Since the stats are now out for a week, I am more and more starting to work on what could potentially be good combination of cards for combat, which should start by the end of the month.
Today I would like to give you an example for a rush deck, which in my view could work nicely. As my own deck is maxed out at every card I will argue with maxed level cards. Also, I will assume 20 Mana fights as this is what is said to be the starting level.
What is a rush deck?
The idea is that with this deck you go for a quick kill of some of your opponents cards. If this works the amount of damage your opponent can do to your deck in each round will be minimized.
Which summoner to chose?
Each summoner can only summon monsters from their own splinter. The exception is Selenia Sky, which can summon Dragon monsters as well as monsters from one other splinter. I think that if you own a max level Selenia Sky it is probably smart to start with this as a summoner as it allows you for a significantly higher variability than other summoners. So I will chose Selenia Sky as my Summoner. She has 3 mana costs and adds 1 damage to all ranged attacks of the monsters on my deck.
General Thoughts
To create a good Rush deck I need to have as many strong attackers which are able to attack the same cards as possible. As Selenia Sky adds to 1 damage to ranged attacks, this fits well to this strategy. I will therefore use as many cards with ranged attacks as possible. Also, ideally I want to be able the opponents tank before it can hit for the first time. Therefore, speed is also important for this deck.
Position 3 - Lightning Dragon
At the very last position I place my Legendary Lightning Dragon. It comes with a ranged attack of 4, which will be increased to 5 due to the Selenia bonus. It has piercing, which means that no attack is wasted if it is stronger than the remaining armor of an opponent. Flying ensures that it can attack very early and is difficult to hit. If it is hit it has Throns which mean that the opponent will also take damage. Last but not least it has the Stun ability which gives it the chance to stun its opponent, which will then have to skip the next round. Its health of 8 is also solid and makes it difficult to kill. The only negative is its high mana costs of 8, which leaves me with only 9 remaining mana available. I will place him in the last position.
Position 2 - Fire Demon
At the second position I will place my epic Fire Demon, which is from the red splinter. the fire demon comes with a mana cost of 4, which means that I will have 5 mana left. Fire demon has a ranged attack of 4, which will be increased to to 5 due to Selenia Sky. Speed at 4 is ok, so it will most likely be quicker than most tanks. Health of 6 is not great, but I hope that this card will be hit only when the worst action is over. It has Blast which means that its strong ranged attack can also spill over to the opponents monster in position 2.
Position 1 - Giant Roc
As my tank I chose the Giant Roc. It costs 5 Mana so my mana is now fully used. At speed 6 and Flying as an Ability, it will attack very early for a tank and will have a good chance of hitting. The Ability Trample means that if it kills an opponents monster it will perform an additional melee attack on the next monster. I am not 100% sure if it will attack first or second as it has the same speed and flying ability as my Lightning Dragon. If it should attack second, chances are good that it might already kill some of the weaker tanks. Its health of 8 are not great, but if I manage to wipe out the opponents tank in the first round, chances are good that it will survive the first round and will be able to perform a second attack.
Overall, I will perform 14 damage points to the first line monster of my opponent. This means that most likely I will have killed the opponent's tank before it can perform any damage on me. In the second round chances are good that I can kill another monster before my tank is taken out.
I would be interested to hear your thoughts on this rush deck? Also 
Wish you all the best with your monsters,
Tim