While the numbers may say that G/B Constrictor made up 10% of the field at Pro Tour Hour of Devastation in Kyoto, I suspect that the G/B players at the tournament were split between the energy version and the delirium version. While both strategies have a lot of overlap, they have substantial differences as well.
I chose to play the delirium version because I think it has a more flexible core that is better capable of transforming into a control deck post-board. Energy has a more consistently aggressive game plan, but lacks the late-game power of a card like Traverse the Ulvenwald to help you when things slow down after game 1. A perfect example of why I prefer delirium is when I played the “mirror” match against the energy version in round 15. We both sideboarded in a bunch of removal spells that made the game play out slower, and in the long game I drew 2 Traverse while my opponent drew 2 Attune with Aether. His got a Swamp and a Forest while mine got a Tireless Tracker and a Verdurous Gearhulk that propelled me to victory.
Generally, you should play energy if you expect a lot of decks like ramp where you want to be aggressive in both pre- and post-board games. Unfortunately, I think those are matchups where you still aren’t going to be thrilled to be playing a G/B deck, so for most metagames where I would choose to play G/B, I would rather stick with delirium. Here’s the deck I played at the PT:
4 Winding Constrictor, 4 Grim Flayer, 0 Gifted Aetherborn
Your 2-drops. Generally speaking, they’re among the most powerful things you can be doing for 2 mana. Constrictor in particular has a ton of synergy with the rest of your deck and can easily run away with the game if it lives. Heading into the Pro Tour, I was expecting Gifted Aetherborn to be excellent against Ramunap Red, but after playing more with it I realized that if any of your 2-drops live you’re usually going to be in great shape anyway, so you should just play the ones that are better against the field at large instead.
4 Fatal Push, 2 Grasp of Darkness, 2 Dissenter’s Deliverance
Your removal. Fatal Push is probably the best removal spell printed in the last 4 years and between Clues, Walking Ballista, and Evolving Wilds, this is one of the best Standard decks at turning on revolt. Grasp is important for killing Hazoret, Archangel Avacyn, and Glorybringer at instant speed, but can be a bit difficult to cast, so you only want 2. Dissenter’s Deliverance is an odd card in that it doesn’t have a ton of super high value matchups these days, but is so low-cost to play that I think you still want it. Getting delirium against decks that don’t have good targets for instant speed removal can be tricky, so having a cycling card is really nice, and having outs to an Oketra’s Monument or God-Pharaoh’s Gift in game 1 can be quite valuable.
4 Walking Ballista, 1 Rishkar, Peema Renegade, 2 Verdurous Gearhulk
Your +1/+1 counter synergy cards. Ballista is one of the most important cards in the deck in the fight against Ramunap Red because they have so many 1-toughness creatures, and if they use Chandra’s 4 damage ability, it only takes 1 counter to kill it. Gearhulk is your most individually powerful card that is easy to Traverse for when you need a fatty. Rishkar is an odd card that I don’t really like all that much, but can be very good to draw when Winding Constrictor lives. You board it out when you want to play a slower game.
3 Nissa, Voice of Zendikar, 2 Liliana, the Last Hope, 3 Tireless Tracker, 2 Kalitas, Traitor of Ghet
Your long-game cards. If any of these cards live for a few turns, they can generate a ton of card advantage and make it very difficult for your opponent to come back. Tracker’s stock is probably at an all-time low because of how fast the format is, but you still can’t really cut down on them too much because of how important it is to have access to them post-board. Kalitas is incredible against red while also being a powerful enough card in other matchups that it’s totally reasonable to play them in the main deck.
4 Traverse the Ulvenwald
This might be the best card in Standard. Early game, it fixes your mana and lets you functionally play 27 lands, but in the late game it’s better than even any creature land could hope to be by turning into whatever threat is most appropriate at the time. I think that in a few years we’ll be looking back at this Standard format and feeling foolish for not all playing 4 Traverse in any green deck.
The key thing to understand about sideboarding with G/B Delirium is that the post-board games are going to be slower and have less of a focus compared to the pre-board games. People are going to have more generic answer cards that line up well against each other, so having access to cards that generate card advantage like Tracker, Ob Nixilis, and Liliana becomes more important.
This also means your sideboarding should anticipate how your opponent’s game plan is going to change. For example, Mardu Vehicles is usually very aggressive game 1 and Walking Ballista is one of your better cards because it kills Veteran Motorist and Toolcraft Exemplar. But in post-board games they usually cut a lot of those creatures and bring in a bunch of planeswalkers and cards like Fumigate, making early removal and Walking Ballista a lot less important. Knowing the ins and outs of these matchups is absolutely critical to success.
Going into the PT, I expected the God-Pharaoh’s Gift to be a little more popular, which is why I was willing to play 3 Dispossess. I found that the games are easy without their namesake artifact because they have so many slots in their deck devoted to getting it into play. I still like the card against U/R Control taking Gearhulks, but I think you probably only want to play 2 and replace the third with a second Doomfall.
3 Transgress the Mind, 1 Doomfall
Some hand disruption, invaluable against decks that try to go bigger than you like U/R Control, or R/G Ramp. Transgress gets the nod here even though Doomfall is more flexible because you have so many 3-mana plays you want to set up with a discard spell that having a better curve is more important.
1 Grasp of Darkness, 2 Never // Return
Some extra removal. Never // Return in particular is important because a lot of people have cards like Chandra or Ob Nixilis in their sideboard and you have to make sure you can kill them even if you've failed to develop a sufficiently large board presence before they come down. Grasp also has increased value in a lot of post-board games because Glorybringer is a fairly common sideboard card.
1 Ob Nixilis, 1 Tireless Tracker, 1 Ishkanah, 2 Gonti, Lord of Luxury
A handful of value cards that are just great in the kind of longer games that tend to happen post-board. Gonti in particular is amazing because it’s nearly a guaranteed 2-for-1 as long as your opponent has good cards for you to hit off it.
0 Yahenni’s Expertise, 0 Cartouche of Ambition, 0 Gifted Aetherborn, 0 Aethersphere Harvester
These are all cards I tried against Mono-Red and found them all lacking. The problem with the red matchup is that post-board they change their deck so much to be about 4- and 5-drops that having any of these cards, which would be great in game 1, really doesn’t work out well enough to justify the sideboard slots.
Remember that it’s important to be fluid here. If your opponent has sideboarded in a way you didn’t expect (like for example if Mardu left in all their cheap cards), it’s important to react to that and have a coherent game plan for each of the post-board games.
Post-board your number one worry is letting a Chandra or Glorybringer come down and take over the game. You should always be mindful of what will happen if they play either of those cards on their next turn (and they run about 6 combined copies of them, so they’ll have it pretty often). It can often be correct to “waste” a Nissa by using its -2 ability to get a Grim Flayer or Kalitas to 5 toughness. I wish there were a better plan post-board here, but I think you just have to accept that they improve more than you do and take your strong game 1 matchup as enough of an advantage.
This is probably your worst matchup because game 1 is so rough. You have a ton of dead removal and Hour of Devastation makes your planeswalkers less reliable than they used to be. Post-board, you transform your deck to be made up almost entirely of cards that trade at a good rate. Dispossess should name Torrential Gearhulk, and with the amount of removal you’re leaving in, it’s often difficult for them to kill you once they no longer have the over-sized Snapcaster in their deck.
GB Mirror (Both Energy and Delirium)
On the Draw
On the Play
Post-board games here are all about grindy card advantage. Many of your cards will trade 1-for-1, so having as many 2-for-1s as possible is key. It’s usually better to use the minus ability on most of your planeswalkers to ensure you get some value out of them rather than trying to ultimate them because of opposing Walking Ballistas and Never // Return being able to shut them down.
They have so much removal that your creatures that are “just stats” are not going to be very good. You want to try to be as controlling as possible and make sure to remove their must-kill creatures on sight. They have a hard time dealing with large Verdurous Gearhulks, so that is often your route to victory.
U/W God-Pharaoh’s Gift
Here you want to disrupt them and kill them with whatever creatures you happen to draw. Never // Return is mostly so you don’t get caught off-guard by a random Gideon or something. You’ll also often have an excellent idea of what removal lines up well after you Dispossess them so you can plan accordingly for game 3.
There you have it! I think G/B will remain at least decently positioned going forward, and I hope you enjoy Traversing as much as I do!