Collected Company with Elves in Standard. I think it kind of acts like a cannon, belting out elves at your enemy...hence the name.
Chord of Calling lets the deck also act in a toolbox manner.
I think playing Sylvan Messenger is a trap. CoCo is how we want to put our elves in play, and the Messenger isn't hit by CoCo either. As I test, and I think trample becomes relevant, I may add one copy of Nylea, God of the Hunt in order to push my elves over the top.
The obvious weakness of this deck is a well-timed wrath or control, especially with discard and/or counters. The Sideboard is aimed to help deal with these.
4x Thoughtseize against control to hopefully throw off their game plan.
2x
Mortal's Resolve
to help protect the best against either wraths or kill spells.
The nice thing is that Languish, Anger of the Gods, and Crux of Fate are all sorceries. So hopefully even if they wrath, you can CoCo at the end of their turn, hopefully make them lose life with Shaman of the Pack, and then swinging heavily next turn.
I've seen people running a copy of Woodland Bellower main deck. This would be an obvious Chord target, but I dislike the card and don't think it's very good in Standard at all. If it could hit Dwynen it might make sense, but this deck is not about brute strength, but rather swarm tactics. That's a very large mana investment that I'd rather be playing to boost my elves with Dwynen.
Any thoughts or comments are welcomed, especially for the Sideboard.