"Mono-Green" Devotion in Modern. It's a kind of solid but not really deck and can be relatively cheap in comparison to other archetypes. It runs a very strong combo finisher that can be fetched with one card (Tooth and Nail into Emrakul, the Aeons Torn and Xenagos, God of Revels) as well as a great midrange backup in the form of large creatures that do fun things.
Now, let's go over the cards.
Main board:
Utopia Sprawl is king in this deck. It is essentially as close as we can get to a Wild Growth in modern. It makes your Forests tap for GG or GR if you need it to fuel your Kessig Wolf Run. So good it takes four spots automatically.
Fertile Ground is almost as good as Utopia Sprawl. We run two of these since we cannot run 6 utopia sprawls.
Harmonize may not look that great, but we need cards. Our hand should be out on the field relatively early and we need a way to replenish it. I mean, it's good card draw in mono-green. Just wow.
Tooth and Nail is our main win condition. We can ramp into this baddy and entwine it on turn four, your opponent permitting. We'll almost always grab Emrakul, the Aeons Torn and Xenagos, God of Revels and swing in for either a lethal or a crippling blow. We can also grab Acidic Slime if we need to remove that Ensnaring Bridge.
Arbor Elf serves to help us ramp, and amazingly well when used in conjunction with Utopia Sprawls or Fertile Grounds. Playing this guy on turn one allows you to drop a four drop on turn two. Let's hit a Garruk Wildspeaker with him and drop a Wistful Selkie after that. If he didn't exist, this deck would not be nearly as good. In other words, he is the MVP.
Voyaging Satyr
serves the same purpose as the Arbor Elf: more ramp. As a two drop, he isn't as great, but he has the added bonus of being able to untap our Nykthos, Shrine to Nyx.
Garruk Wildspeaker serves as another great form of ramp as well as some utility. Most of the time he will untap an enchanted Forest and a Nykthos, Shrine to Nyx yielding a great amount of mana. But, if you need some bodies, just minus him for a beast. Or if he can ultimate and you have enough bodies on board, just use his Overrun and win the game there.
Eternal Witness fetches us a card out of our graveyard and the ability is on a creature giving us two more devotion? What isn't to love? Whether we need to grab a Harmonize for some more card draw, a Windswept Heath to hit a land drop, a removed Primeval Titan or Garruk Wildspeaker, or an unsuccessful Tooth and Nail, he will get us there. Can even drop him just to gain two devotion. He just works.
Wistful Selkie is an amazing card, albeit he is open to most removal in modern. But, he replaces himself in the form of card draw and he gives three to our devotion count.
Acidic Slime as a one of to hit those Ensaring Bridges, tron lands, other man lands, or really any non creature permanent that needs to bite the dust. If you are feeling particularly cocky, replace him with a Terastodon that you can cast on turn 3 and destroy all their lands. But, sniping one trouble permanent is usually enough and five mana is much easier to cast than something at eight.
Primeval Titan, what can I say about him? Well, he can hit the board as early as turn three, gets me two land when he enters, two land whenever he attacks, and is a huge threat just as a 6/6 trample. However sadly, he is usually countered or killed when he hits. If you've played him or seen him played, you know he can be the real deal.
Emrakul, the Aeons Torn is part of our primary win condition. He can be hard cast as early as turn 4, or Tooth and Nailed into play on turn 3.
Xenagos, God of Revels is the other part of our win condition. We grab him and Emrakul, the Aeons Torn with a Tooth and Nail and swing with a 30/30 annihilator 6. If the opponent isn't dead they will be crippled.
Misty Rainforests and Wooded Foothills just helps us thin out our deck. Get those pesky lands out and hit some fatties. In a pinch they can also be grabbed with an Eternal Witness to hit a land drop.
Forest because it's green and we kind of need that, but I might be wrong.
Kessig Wolf Run because it's a great sink dump for our purposes.
Stomping Ground because we need reliable red mana for Kessig Wolf Run and we want to be able to cast Xenagos, God of Revels as well as Blood Moon.
Boseiju, Who Shelters All to get around those pesky counter spells, make sure to fetch it off a Primeval Titan. Tooth and Nail and Harmonize are both spells that you want to happen and this is a great way of doing that.
Side board:
This deck is hard to sideboard and it should be changed for your meta. Anyhow,
Chalice of the Void is great in here when we set it at two. It turns off a whole four cards in our deck, can come out as early as turn 2 with 2 counters on it. It can be a complete blowout. However, with the nature of this deck, it could be something better. I just like playing it.
Beast Within is removal for anything, a catch all of you will. We generally will not care if they get a 3/3 beast, our creatures are generally much better. I bring this in to deal with Liliana of the Veil or other permanents I have problems with.
Fracturing Gust because Affinity is a thing. Let me go ahead and blow up your board AT INSTANT SPEED and gain all that life back. Just hope they animate their lands first. Also good against Boggles and the occasional Enchantress deck.
Blood Moon is Blood Moon. Such a high percentage of decks almost say GG to Blood Moon so it's definitely worth running. While it does hurt us, we only need three green sources to reliably go off. Between your Forests, utopia sprawls, and Fertile Grounds you can work around the restriction. If you sided it in, play your lands and enchantments with that in mind. While it does hose Nykthos, Shrine to Nyx, we don't really need it. More often than not, Nykthos, Shrine to Nyx just helps us go over the top. Note that a resolved Blood Moon will remove all Utopia Sprawls from Stomping grounds.
Nature's Claim is there as more hate against Affinity, Twin, Boggles, Enchantments, and can even be used against burn to blow up your own enchantments to gain some life.
Obstinate Baloth helps us gain some life in aggro matchups while providing a large blocker and some devotion. Also great against LotV. I used to have Wurmcoil Engine in this spot, but the two mana difference is huge and makes Obsintate Baloth a better pick.
Maybe board:
Trinisphere is one of my favorite cards. By the time this comes out, you don't really need to cast any of your smaller things. This is great against Affinity, but mainly against Storm. They just play pass go if you get this down early. The only problem with Trinisphere is that it is lackluster as a top deck in late game. It could be replaced but I enjoy seeing people's faces when this comes out.
Leatherback Baloth
: a three drop 4/5 that adds three to my devotion is great, I just cannot find a spot for him right now. I used to run a playset until I discovered Wistful Selkie. The cantrip is almost always better.
Asceticism adds extra protection for my dudes, but playing with it I would find I wanted almost anything else in my deck when I drew it, it was often a dead card.
Khalni Hydra
is a huge rock for devotion. He usually comes down relatively early, but at this point the card feels more win-more than useful.
Primalcrux is also not in here as he is just a huge beater. He comes down and dies. Primeval Titan is much more relaxed mana wise in that spot and if he bites removal, we got two extra land into play anyhow.
Sowing Salt
or Crumble to Dust as an answer to Tron, but with the current meta, Blood Moon feels much better.
Nylea's Disciple is a card I played with for awhile, but the games where I needed life were the games where I had no board presence. So I replaced it with Wurmcoil Engine and then Obsinate Baloth. I'm just leaving it here so no one drops it as a suggestion.
Scavenging Ooze was great was Pod when running rampant. But now he feels very lack luster for this type of deck and was cut.
Arena
feels good against other mid range decks but the lack of a mana ability limits it severely. However, when I could get it off, it was never needed.
Thrun, the Last Troll is good in a control heavy meta, which ours is not.