Green

Thanks to MtG:Salvation user Frenadol for providing the lion’s share of the content on this page. I’ve added my thoughts here and there, but this writeup is primarily his. I have edited his content for clarity and formatting. Some of the information below may now be outdated due to the printing of Sanctum Prelate and Recruiter of the Guard.

GW Taxes

The green splash in D&T tries to patch some of the deficiencies of the more common mono-white lists. The splash offers card selection and advantage while also improving the overall creature quality and flexibility. These creatures, in turn, allow the deck to lean less on non-creature answers to the opponent’s plays. The splash also provides a wide variety of effective silver bullets against blue decks, making it shine in a heavy blue meta with traditional decks such as Miracles and Delver lists, while also being effective against midrange lists like Shardless BUG.

Why would you play a green splash?

GW lists thrive in a heavy blue and fair metagame. For example, in the Dig through Time and Treasure Cruise era, the green splash was devastatingly good at stopping these powerful draw engines with Gaddok Teeg.
To gain access to maindeck artifact/enchantment removal (Qasali Pridemage) and card selection (Sylvan Library)
Your sideboard becomes more flexible with harder hitting silver bullets and more access to wide application cards.

When is not a good time to splash green?

If the metagame is full of non-blue decks, there is less incentive to play powerful sideboard cards like Choke or Carpet of Flowers that are major reasons to splash green in the first place.
GW Taxes does particularly well in any metagame where traditional D&T thrives. The splash build has many of the same strengths as traditional D&T while also improving on many common matchups, with the exception of non-blue aggro decks like as Burn. A metagame which is not favorable towards traditional D&T is also not going to be great for GW D&T either.

Key Cards

When splashing green, these are the most important cards to consider. These are the cards that give the GW version its own identity.

Qasali Pridemage: This cat is in my opinion the single biggest reason you should consider splashing green for. Maindeck artifact and enchantment removal has traditionally been one of the main weaknesses of D&T; even in post-sideboard games, most of the good options in traditional D&T don’t play well with Thalia. While Phyrexian Revoker can do some work against equipment, the card only works as long as it stays on the battlefield, making setting up blowouts easier for the opponent. A permant, maindeckable removal card can be invaluable against many common matchups. Pridemage destroys the equipment in the mirror, Counterbalance against Miracles, and even problematic sideboard cards like Dread of Night. Its 2/2 body for 2 mana is also great against -1/-1 effects and Exalted brings a ton of extra combat utility, synergizing particularly well with Serra Avenger and Mirran Crusader.

Sylvan Library: One of the biggest deficiencies of Death and Taxes is that, it doesn’t run any card selection (e.g. Brainstorm, Ponder). This indirectly makes long, drawn out games worse for D&T, as you are playing with whatever comes off the top of the deck with little say in the matter. Sylvan Library is particularly strong against Miracles and Stoneblade decks which play Swords to Plowshares and try to play the control game, leaving you with plenty of time and life to draw extra cards. Fetchlands and Stoneforge Mystic provide a reasonable amount of shuffling to get rid of the less useful cards.

Gaddock Teeg: Teeg is a very versatile sideboard card with application in a wide variety of matchups; his two distinct abilities mess with a surprisingly large portion of the format. He is also a Legendary creature, meaning that like Thalia, he can be protected by Karakas. Teeg is a a good card in a blind or varied meta with lots of Tier 1.5 or 2 decks, hidering everything from Nic Fit to Stax to Tezzerator. Teeg shines against Miracles and Elves, as it cuts off some of their most important cards (Terminus and Jace, the Mindsculptor; Natural Order and Green Sun’s Zenith). It also improves combo matchups (especially ANT) by complementing cards like Ethersworn Canonist, which are often mediocre in multiples.

Choke: Another sideboard card that would usually take the place of the sideboard resource denial card Cataclysm and/or Armageddon. The upsides are obvious and so are its downsides. Against blue decks it has potential to be much better than Cataclysm by being asymmetrical, and against decks with only Islands in their manabases (Delver decks for the most part) it’s usually game as the card straight locks them out of the game once it resolves. Its CMC of 3 also helps it being cast without much issue, and it even allows you to leave mana up for Daze or Spell Pierce consistently. It’s also much easier to cast with a Thalia in play. The obvious downside of Choke is that it doesn’t work at all in matchups where Cataclysm would’ve otherwise been good, the best example of which is Nic Fit. It also has diminishing returns against Shardless BUG if the opponent knows your list and plays around it. Overall it’s a great card that will give you plenty of games for free in an unknown meta such as a big event, since nobody really expects Choke coming out from DnT.

Other green cards to consider:

Carpet of Flowers: Definitely one of my favorite cards to splash for, it vastly improves the Delver and combo matchups. It allows you to generate additional mana in the early game, freeing your lands for mana denial earlier than normal. There’s also a positive feedback synergy with Rishadan Port. Once you start tapping their lands, you force them to play more lands, which, in turn, generates you more mana and frees even more of your landbase for the mana denial plan. Carpet draws a lot of parallels to Vial in the way that it accelerates your board while freeing up your lands, but while it doesn’t give your creatures “Flash” off of Vial activations, it does make non-creature cards in your deck vastly better. You can make some really disgusting plays such as turn 2 Choke, or turn 3 hardcast Jitte/Sword/Batterskull, equip, and attack. Getting to 8 mana to permanently protect Batterskull by bouncing/hardcasting is also very doable.
Carpet on turn one also nullifies most of the tempo advantage your opponent gains by being on the play by allowing you to play generate one extra mana on turn one for Vial or Mom. After playing Carpet, you potentially have four mana on turn 2 or 3, putting you far ahead of most fair decks.

Ground Seal: This is a cantripping version of Rest in Peace and an answer to widely played creatures such as Snapcaster Mage or Deathrite Shaman. It has obvious downsides compared to Rest in Peace, but it’s a card to consider if you face many decks that otherwise make siding RIP in very inefficient, such as against 4c Delver or Miracles/Stoneblade with many Snapcasters. It has utility against targeted reanimation cards in the Reanimator matchup but doesn’t hit Exhume.
Yisan, the Wanderer Bard: This is a great creature-based card advantage engine. You can just get traditional creatures like Mom, Avenger, and Flickerwisp or you can opt to build a toolbox around it. It has a decent sized body, is easy to protect, and the ability is a great mana sink for the long games. This is an excellent one-of to consider in slower metagames.
Mana dorks such as Noble Hierarch and Deathrite Shaman. Can be good situationally but their function overlaps with Vial.
Mayor of Avabruck for lists with lots of Humans or Naya builds with Imperial Recruiter and Magus of the Moon.
Hidden Gibbons: 1 mana 4/4 against a good chunk of the metagame. Great against Delver, or just about anything with Brainstorm.
Loaming Shaman: Creature based graveyard hate which can be searched out with Yisan. Works well with Flickerwisp.
Silver bullets like Compost and Skylasher.

Manabase

Most GW lists I have tested run the same number of lands as normal mono-W, which is 23 lands, and keeps the full package of resource denial. Green mana is most often generated by a 5/3 split of fetchlands and duals, with a Horizon Canopy as extra utility, but that can be substituted for a fourth Savannah if the 1 life loss is a concern. In Yisan lists, a basic Forest is a choice worth considering as it’s relatively easy to get Wastelanded out of green if you get Yisan onto the battlefield and doesn’t want to see him get out of control. Any white fetchland is okay but you might want to run less widely used fetches such as Marsh Flats and Windswept Heath if you want to cheese someone with Pithing Needle. Windswept Heath is required if basic Forests are used.

A general purpose manabase would look like this:

5 White Fetchlands
3 Savannah
3 Plains
4 Wasteland
4 Rishadan Port
3 Karakas
1 Flex Slot

The flex slot is usually an extra green source like Horizon Canopy but it can be whatever you want depending on your particular needs.

Sample Decklists

Updated standard list, fairly balanced against a general metagame

Matchup considerations

Miracles: Easier. Gaddock Teeg is huge in this matchup, and the maindeck has access to permanent removal for Counterbalance. Choke is a great finisher. Library allows us to maintain parity with them as long as we want, never forcing us to overextend in order to close games before it goes out of hand.
The mirror: Easier. Qasali Pridemage destroys equipment and makes our creatures bigger for favorable attacks. Library gives us better lategame than normal DnT.
Eldrazi: Unchanged to slightly harder: The splash doesn’t help much in terms of what it bring to the matchup, while having a manabase with more nonbasics leaves us more exposed to Wasteland.
Grixis/4c Delver: Easier. Carpet of Flowers and Choke shine here, but the decision whether to run Carpet or not is up to the player, but this matchup is where it really shines. Otherwise the matchup is still favored compared to mono-white, albeit not as much. GW runs fewer Revokers by default and Pridemage does in general better here but neither of them are ideal cards. Postboard Pridemage can deal with Null Rod and Sulfuric Vortex if they run those cards.
UR Delver and Burn: Harder. More nonbasics means more damage taken with Price of Progress, and there isn’t really a great way avoid it other than siding out all green cards and fetching basics only, which is still doable but not optimal. Dedicating sideboard space to the green goodies means less space for traditional Red hate such as Circle of Protection: Red off a Tutorboard.
Lands: Mostly unchanged. Qasali Pridemage can destroy Exploration and Manabond, which slows them down. Otherwise there isn’t much difference.
Esper Mentor: Easier. Library and Choke can do wonders here although it still depends on whether you can find the StP for their Mentor become being ran over, and Library help in that regard.
Shardless BUG: Mostly unchanged. This matchup depends on your white base rather than the splashed cards, so the splash doesn’t really matter unless you run Carpet of Flowers. Choke has moderate to limited utility depending on whether the opponent knows you have it, and it’s about as good as Cataclysm here. Carpet of Flowers is still very useful in this matchup because of its synergy with Batterskull, helping you reach the magical number of 8 mana and stealing the game from them. This is the only matchup where I side out 2 Vials out, for 2 Carpets.
Storm: If your sum of Teeg and Canonist is greater than the number of Canonists in your mono-white list, then the matchup gets easier because you have better chances of drawing one in addition to the Thalias. Not much else to say here. Storm is also a blue deck so Choke and Carpet are still very useful. Choke with Thalia usually means game since it prevents them from getting the chain started.

Conclusion

The green splash for the most part helps improve our traditional even or good matchups, and also makes the deck overall more consistent by having wider application cards in the maindeck, but it doesn’t magically make previous bad matchups (Elves!) much better, although it all depends on how you decide to build it. Green has a wealth of sideboard tools that can be used to adapt the deck to your own tastes, and as I said in the beginning, it’s a great variant to consider in the right metagame, but even in a not so favored metagame it can still perform well, as, out of all the splashes, it plays out the closest to mono-white because of the overlap between what green and white bring to the table.

Stock GW Taxes

Yisan Toolbox list

Sisay Toolbox list