You may have noticed quite a lot of articles based on sideboarding here at QuietSpeculation--a resource not commonly found on most Magic sites. Personally, I find the effectiveness of this often overlooked tool to be inversely related to the size of a format.
That is to say that I'd be very happy jumping into block constructed with a deck and a guide, whereas I would feel completely unprepared with the same tools in Vintage. I'm of the belief that there is just too much going on in Modern to be ready without knowing the theory behind a sideboard, rather than simply knowing the most anticipated applications.
You're an odds-on favorite to play against at least one deck that your sideboard guide neglected to mention. There's also the fact that sideboarding guides become less useful the more that you deviated from the list that they were written for--especially as the guide ages and the metagame evolves.
For that reason, instead of offering a sideboard guide to be consulted on the fly, I would like to offer the reasons I've constructed my sideboard the way that I have as well as considerations for other cards as a guide to be studied in preparation for an event.
To get started, let's look at the sideboard that I presented last week:
Now let's talk about why I selected each of these cards.
Negate is sort of a no-brainer to me. There are quite a few problematic spells in Modern, and by problematic I mean that I lot of them just kill you if they resolve.
This is far from an exhaustive list of things worth Negating. Burn and Hexproof also give incentive to this inclusion, as dealing with any enchantment or burn spell can mean a world of difference in those matchups.
Dispel and Spell Pierce are nice, but Pierce is only effective against particularly spell-saturated decks and decks that try to operated on very little mana, and Dispel, while more efficient, can't handle sorceries or planeswalkers.
The simple truth is that Affinity is strong enough and popular enough to warrant specific hate. I'm not big on having cards for one matchup and one matchup alone, and that's why I chose Sabotage. Specifically, being able to counter some artifacts is much more powerful than being able to destroy them.
Annnnnnnnnnnnnd, sometimes you play one slot just for Affinity. They don't really fight fair, so I like having at least one thing that really hoses em. It's possible that there are non-affinity decks that Hurkyl's Recall is good against, but I couldn't even begin to imagine what they'd be. Maybe some poor soul is playing Trading Post?
As stated above, this card is for spell-saturated and mana-light decks with important spells. I primarily added Pierce as an efficient way to interact with Hexproof decks. It also has applications against various combo decks as well as Burn. It's pretty useless in grindier matchups, but there are exceptions to be made. In particular, I brought them in against an opponent wielding Smallpox.
Fighting counter wars? Burn? Tempo mirror? Instants are the most powerful card type, and often enough there are specific instants that are the most important cards in certain matchups. It's pretty narrow, but there isn't a better card to counter a Lightning Bolt with... Mental Misstep aside...
It's really awesome having access to this card with blue decks. This card does work against Twin, Infect, and anything with Tarmogoyf. And I hear that people are playing Phyrexian Obliterator. I like it against any creature deck that isn't burn heavy. The four life is certainly a liability, but it's hard to argue with Dismember's raw efficiency.
Initially I included Molten Rain as a way to mess up Tron decks, but it also has some other random value. Killing manlands isn't for nothing. The most creative that I've gotten with Molten Rain was bringing it in on the play against Living End. I figured that having a way to push back their fundamental turn would be useful, and I even won a game off the tempo that a turn three Stone Rain generates. It also might just be right to bring this in against the Green Devotion deck with all those Wild Growth effects.
This is mostly for ignoring counter-wars against Twin. The other strong consideration for Combust is Restoration Angel, as being able to kill a four-toughness creature at instant speed is an uncommon commodity. And, of course, you bring it in when your opponent plays a lot of blue and/or white creatures. Like Merfolk.
Kitchen Finks and Voice of Resurgence can be serious problems. While the maindeck features Pillar of Flame, the instant speed is considerably more relevant out of the sideboard. Obviously it's not a boon against Voice, but being able to, say Magma Spray a Kitchen Finks in response to the lifegain trigger when your opponent has an active Birthing Pod makes a world of difference.
Spray will also come in against any aggressive deck with a low curve, and while that's not the most exciting card, it has more utility than just playing something like Burst Lightning.
Yet another card for Hexproof. It also hits tokens, and I'd bring it in against anybody who is heavy on one-drops. In particular, I'd look out for a Wild Nacatl deck filled with Kird Apes and Loam Lions as opposed to one with Knight of the Reliquary and Thundermaw Hellkite. I wouldn't bring it in in order to deal with two drops, as Spell Snare is just going to do a way better job.
Graveyard strategies aren't especially prevalent in Modern, but they are around enough to warrant some hate.
I like Relic over other options for a few reasons. It can hit the entire graveyard, one copy can fight existing and future cards in graveyards, and it replaces itself when needed. It's also the only kind of graveyard hate that I believe is worth bringing in against decks with only Snapcaster Mage interacting with their graveyard. It's also a nice one to have against Grim Lavamancer, which is starting to matter as the mirror becomes more popular.
Of course, all of these spells come together as a tool against the problems that I believe are most likely to need to be addressed. There are quite a few other options, and in such a wide format it's really just impossible to include every card that you could possibly want in your sideboard. The following is not an exhaustive list of possible sideboard options, but it's a pretty long one.
Other Graveyard Hate
All of these options are fine, though their applications are clearly different. It's definitely worth noting that Grafdigger's Cage is completely useless against Living End due to some interesting wording, so don't get caught pants down there.
Decks based entirely on the graveyard just aren't popular enough for me to play any of these over Relic of Progenitus, but Tormod's Crypt would probably be my weapon of choice if they were due to sheer efficiency.
It's tempting to play Surgical Extraction due to synergy with Delver and Snapcaster Mage, but it doesn't do much against Living End and just isn't worthwhile against something like a Gifts Ungiven deck that Relic of Progenitus can hose more completely all while replacing itself.
Blood Moon turns off all of the Trons and manlands, and can really punish particularly greedy manabases. I personally shy away from cards like Blood Moon as they are high-variance. Fetching for basics, being ahead when the Moon comes down and just drawing enough Urza's Mines to start casting Wurmcoil Engines are all ways to beat Blood Moon, and it's impossible to know exactly how a game is going to play out while you're sideboarding. It's clearly a powerful card, it's just completely outside of my comfort zone.
Electrickery is another option for dealing with tokens, and at times it can be quite effective against Hexproof. It's also a neat little breaker in the mirror. I could see running one copy, though it's pretty narrow so I don't think I'd do two.
Pro Tour Born of the Gods champion Threads of Disloyalty is definitely worth a look. I'm not huge on three mana spells, particularly when they don't flip Delver of Secrets // Insectile Aberration, but stealing Tarmogoyf is a big game.
If you're looking for something a little slower but a little higher impact than Threads, then Vedalken Shackles is a fine option. Shackles has implications against Twin that Threads doesn't, though it can be tough to actually hold a Tarmogoyf with it. It's definitely mana intensive for this deck, but the card's power level is undeniable.
It's a threat and it's solid against decks like Scapeshift that hinge on a specific card. Personally I prefer to just use counterspells, as they force your opponent to commit mana, but a clock with some built-in disruption is certainly worth a look.
Counterflux is awesome in the same way that Dispel is, in that it fights counter wars very well, but, unlike Dispel, Counterflux isn't the most efficient way to combat opposing removal spells and burn. It's a catchall and an awesome answer to Snapcaster Mage, with the biggest liability being that it's pretty mana-hungry for this deck. I wouldn't play more than one, but one can be pretty good.
I tried this one out for fighting against grindy decks like Jund, but it ended up not playing out the way that I would have liked. -1 makes it weak to Lightning Bolt while +2 makes it weak to Abrupt Decay. I also wanted it against combo decks, but you often can't cast it until you get to five mana for fear of not leaving up counter mana. Jace isn't a terrible option, but I like it more in a deck that's looking to make more land drops.
It's also another option against Burn and can be a surprise one-shot Spellskite against Hexproof and Twin. I think it's too narrow, but the upside can be really high.
Then we have Spellskite proper. This is possibly the best option against Hexproof, though it doesn't do a ton otherwise. You can use it against Twin, but don't be surprised when they're ready with Flame Slash. Against most removal heavy decks they'll be able to kill your Spellskite and your Delver, but I absolutely advocate this card is you're expecting to play against a lot of Hexproof.
This is another one that I'm stretching on, but I've lost to Jund a lot when they just killed all of my guys. The clock on Stalker is probably just too slow, but if you're playing Sword of Fire and Ice, it might be worth a look.
Speaking of swords, this one is pretty good against combo decks and green decks alike. I shy away from it due to the fact that five mana is tough, but the impact is definitely high.
This is a good sideboard option for all of the reasons that I'm maindecking one. It can bounce Pyromancer Ascension or Goblin tokens against Storm and it's just a quality tempo catchall.
These are probably the best potential options that I decided against. Sorcery speed makes some of these weaker due to Cranial Plating, Ancient Grudge requires a greedier mana base and I feel like Hurkyl's Recall should do more than Smash to Smithereens' three damage. These are all powerful though, and I'm only really surprised when I see Shatterstorm, as costing four is quite restrictive and sometimes too slow against Affinity.
While I'm reaching, I might as well really reach. Mutagenic Growth saw maindeck play in some Delver decks while it was in Standard and it can really embarrass a Lightning Bolt. It's pretty narrow, and if it shows up anywhere it should probably be in the maindeck, but I could see it being pretty awesome in the mirror.
I really like this guy in Legacy, and many of the things that make him good there exist in Modern. Sulfur Elemental can really swing games against Soul Sisters, Tokens and Death and Taxes, though these decks all generally have access to four Path to Exile as well as creatures that can survive despite losing one toughness. It's a strong option, but one that comes with some inherent risks--not the least of which being facing down a single Honor of the Pure.
Batterskull showed up as a one-of in Delver sideboards when it was in Standard, and I wouldn't discount it as a Modern option. You'd only want it for grindy, non-combo matchups, but it does offer you some inevitability there. It's an interesting option against Jund, as they can often just kill all of your guys. Batterskull forces them to have exactly Maelstrom Pulse... or a 4/5+ Tarmogoyf... Baneslayer Angel can race Progenitus though, so I wouldn't discount this option entirely.
But What Do I Board Out?
This question, more than anything, is where experience with the deck is going to help more than a simple sideboard guide. Especially considering that the card you board out most often is Gitaxian Probe. It's pretty obvious where Vapor Snag and Pillar of Flame are going to be terrible, and those are the most common cards that I board out after Probe. Ultimately, the answer to this question is dependent on your specific 75 and the game plan that you're trying to craft for every matchup.
I hope that this look at sideboard options is helpful, and am very interested in hearing feedback with regard to providing this type of content. Love it? Hate it? Let me know!
Thanks for reading.