I'm aiming for this to be a fairly midrange deck, that can play aggro when needed to combat some of the tap decks in this meta. I really want to build a deck that surrounds the +1/+1 counter function, without having to rely on Energy.
Here's my choices and why they made the main deck:
Winding Constrictor - this one is pretty obvious because the card is the namesake of the deck. The deck is built around the synergy with spells that add +1/+1 counters and the Snek.
Gifted Aetherborn - A hands down great t2 play. And when it gets big with the help of the Snek, it becomes a massive presence on the board. A 2/3 lifelink, Deathtouch for 2 black mana sounds like a great deal to me. The only foreseeable downside is the fact that it's only REALLY useful t3 on, 2 black mana on t2 is kind of hard to come by, and it dies to Fatal Push.
Yahenni, Undying Partisan - Pretty solid t3 board stabilizer. Haste is a great ability and she can become a massive problem when left alone for too long. Pretty solid against aggro and other midrange matchups that play a lot of 2/2 and 3/3 creatures since the deck runs so much removal, she gets really big really fast and can help flip the board in a matter of a few turns.
Rishkar, Peema Renegade - obviously the +1/+1 counter synergy helps a ton, along with the second static ability helping to reach the cost of some higher cost creatures like Gearhulk, or double green cost cards like Maulfist and Nissa.
Maulfist Revolutionary - helps build up some creatures with its enter/exit the battlefield ability (especially when Constrictor is on the board), not to mention a 3/3 for 3 is pretty nice.
Rhonas, the Indomitable - Rhonas gets down and dirty, usually when he comes into play, he can attack pretty quick, and a 5/5 indestructible, deathtouch for 3 mana is just stupid. Plus his ability helps boost some creatures to lethal.
Walking Ballista - pretty obvious again, the Constrictor synergy is really nice, along with being able to shoot directly at the opponent and their creatures for even more removal. I went with a 4 of because I felt like this card is really a staple in the deck and is very powerful in the current standard scene. It's an all-around great card and is a solid play at almost any point in the game.
Verdurous Gearhulk - one hell of a bomb. 5 mana, with the possibility to put +2/+2 on 4 creatures I control is absolutely nuts. Even asa standalone, 8/8 is one tough card to play around.
Nissa, Voice of Zendikar - really another Black/Green staple. Her -2 is absolutely stupid and hitting it with a constrictor on the board is just nuts. For only costing 3 mana she's a solid mid to late game play. She's one of the cards that really makes this deck run. Only real reason I didn't want a 4-of was because of the Planeswalker rule, and I want to minimize dead cards in hand.
Fatal Push - hands down the best hard removal spell in Standard at the moment. Great early game play to help shift the board in your favor, as well as hitting revolt to kill bigger creatures too. All in all, an easy 4-of.
Grasp of Darkness - with the amount of RDW and Zombies playing big creatures (especially Hazoret and Diregraf Colossus) I really felt like this card was helpful in shaking up the board. Only 2 mainboarded because 2 blacks is hard to hit consistently when needed.
Dissenter's Deliverance - because of matchups like Monument and Vehicles. And in other matchups, if it's dead, it easily cycles away. I think it's a very helpful card all in all and is useful in most matchups.
Transgress the Mind and Lay Bare the Heart - point blank hand disruption. Transgress because of its ability to hit legendaries, and Lay Bare because it can hit anything but legendaries. Trying to cover all my bases.
Yahenni's Expertise - Board wipe (most often for just the opponent, and not me, along with being able to play a free card out of my hand, really nice. Useful again in matchups with lots of creatures.
Any card suggestions or number changes are VERY encouraged. And I need help building and understand a sideboard for this particular build of the deck.