Pick your poison, unblockable creatures with +1/+1 counters or mill?
Summary:
This deck wants to do one thing. Build up a huge board, draw into answers, and then smash face. Tishana can grow incredibly large and then you can spread some damage around or just outright kill someone with commander damage.
Card draw:
With Tishana,the Voice of Thunder at the helm, you can pretty much almost always draw into answers or gas. Throw in some extra card draw like Rishkar's Expertise, Prime Speaker Zegana, Harmonize, Hieroglyphic Illumination, Toothy, Imaginary Friend, Rhystic Study, and Soul of the Harvest, things can get out of hand very fast.
Wincons:
Board presence. Green almost always wants creatures on the board and Tishana draws based on how many creatures you control. Get a Ridgescale Tusker and a Herald of Secret Streams out, and nothing short of a boardwipe can stop you. But even then, you have the control elements of blue to help you lock down the board.
The second wincon of the deck is mill. Its a very minor wincon, as only one card helps with that and that's one of the new enchantments from M19: Psychic Corrosion! Whenever you draw a card, each opponent mills 2. Sounds pretty meh, right? However, remember just how much card draw we're running in the deck. An example would be casting Rishkar's Expertise with Tishana on board and 10 cards in hand. You draw 10, everyone else mills 20. If you can chain card draw spells, this can very quickly mill decks out.
Ramp:
We run the usual ramp package in this deck. Cultivate, Grow from the Ashes, Farseek, Skyshroud Claim and anything that ramps us. However, how about we make use of all the creatures we have? Let's get Cryptolith Rite and Song of Freyalise out on the board. Now all your creatures can tap for mana. Let's make things better and throw in Paradox Engine. When comboed with Cryptolith Rite and Soul of the Harvest, you can essentially have infinite mana and draw as many cards as you like, provided you keep casting creature spells, which also ties into the mill plan we have going for us.
Removal:
The deck runs an arsenal of counterspells, bounce, artifact and creature destruction. From Cancel to Krosan Grip to Beast Within to Reality Shift, the deck has answers for most problems. We run only 2 major boardwipes in Cyclonic Rift and Aetherspouts. Cyclonic Rift is pretty much an auto-include in any deck running blue, but not everyone expects the Aetherspouts. Both of these cards can net you massive value if timed correctly, not to mention the political mileage you can acquire from saving someone's life.
Protection:
Besides the usual suspects in blue, this deck doesn't have a lot of protection against flyers. Except for Sandwurm Convergence. This 8 CMC card from Amonkhet is pretty low-tier on its own, but when paired with blue's plethora of counterspells and bounce, punching through the shield isn't as easy as many people would think. Not to mention the 5/5 Wurm it gives to contest the board on the ground.
+1/+1 counters:
+1/+1 counters is another route that this deck can take. Ridgescale Tusker, Rishkar, Peema Renegade, and Hadana's Climb are the main sources of +1/+1 counters in the deck, especially when comboed with Pir. Even the most inoccuous and harmless of creatures can be deadly with a few +1/+1 counters on them. To ensure damage gets through, Crowned Ceratok and Herald of Secret Streams are there to ensure it happens. Vorel of the Hull Clade is also in the deck to serve as a value engine for creatures that already have +1/+1 counters on them.
Deadeye Navigator:
Deadeye Navigator gets a special section here. With its soulbond ability that allows itself and the paired creature to flicker, you can get multiple triggers off your big value creatures like Zegana, Tishana, Ridgescale Tusker, and Rishkar.
