This deck's plan is to build up large, evasive creatures and protect them with counter magic. The primary agent of this is Lorescale Coatl. It comes down on turn 3 and is a 4/4 on turn 4 when it attacks. With Birds of Paradise, this can be sped up by a turn. Brainstorm is an instant speed draw spell that pumps Lorescale Coatl by 3. A Rancor makes this creature even harder to ignore.
To ensure that the Coatl stays around, we have Simic Charm, Mana Leak, and Mystic Snake. The charm can be used to protect all our creatures from targetted spells, but is also useful to help slow down the game by bouncing our opponents creatures. The +3/+3 is the least useful, but can occasionally give enough oomph to end a game. The counterspells are more general answers. Mystic Snake is a bit expensive, but it comes with a body and becomes relevant about the same time Mana Leak stops being useful. It synergizes with Fathom Mage as well and can add a cantrip if the mage hasn't evolved yet.
Finally, there is a nice draw engine in the deck. Give / Take can easily draw us a lot of cards while strictly improving our board state. Bioshift + Fathom Mage
can be quite useful by "removing" counters from Lorescale Coatl. Since we draw for each counter, we put back every counter we remove and then some. Llanowar Reborn gives us another way to move counters onto Fathom Mage for extra card draw, though can buff our other creatures if necessary. Prime Speaker Zegana usually doubles the counters on a Coatl while netting us a ton of cards but, even with the other creatures in the deck, comes down at just the right time to replenish our hand. A Howling Mine helps our opponent, but it usually helps us more. We have a lot of control elements and synergize well with the extra card draw. It can also help us fix a hand with poor mana by letting us dig deeper into our deck as early as turn 3.
Our Plan A is to beat down with Lorescale Coatl though we can easily play the control game with Simic Charm, Mystic Snake, and Mana Leak. Icefeather Aven gives us more bounce effects if we need it but can also support our beat down plan with a large flying creature by using Bioshift
+
Lorescale Coatl
(we can use with Birds of Paradise to similar effect).
