I learned about acceptable nonsynergies before I learned to use sleeves. There was a guy at my shop who would board in Wrath of God in his White Weenie deck. The idea was, no one would see it coming, and he could hold back threats to punish the inevitable overextension.
The MTGSalvation Wiki defines a nonbo as “An interaction between two or more cards that is disadvantageous instead of having a profitable effect (which would be a combo).” The cited example is Crystalline Sliver plus Magma Sliver.
There are two main reasons to run a nonbo in competitive tournament Magic. The first is power concerns, where both cards are that much better than other options. The second is when a deck has a specific need or weakness that only a specific card or cards can solve.
Some of these examples don’t see much play (for good reason). Others are downright reasonable.
Engineered Explosives + Stony Silence
At the core of a lot of these is the idea of: “Well this sucks for both of us, but it sucks so much more for you.”
While a sideboard Stony Silence will shut off your Engineered Explosives, it’s an acceptable bad beat because you’re probably winning. Meanwhile, if you don’t have Stony in play, the Explosives is going to be a great card for stabilizing the board.
The one time the nonbo nature of it comes up is if the opponent is grinding you down with an Etched Champion and you can’t use your Explosives to get rid of it.
Spell Pierce + Path to Exile
Spell Pierce and Path are a nonbo simply because if you ramp your opponent, they have more mana to pay for Spell Pierce. While not ideal, it can be fine if you need the effects for different matchups. If you’re only Piercing the spell-based combo decks, and only Pathing the creature-based aggro decks, then the nonbo never has a chance to come up.
Of course, most decks are a mixture of creatures and spells, and you just have to hope you draw your cards in the right order.
Path to Exile + Tectonic Edge
On paper, these two are extremely polar. One wants to exchange an opponent’s creature with a land, accepting card disadvantage for raw efficiency, and the other wants to trade 1-for-1.
On the plus side, Tectonic Edge is rarely playing the “mana screw you out of the game” role that Wasteland does in Legacy. While it happens, the main purpose of the card is to hit utility lands like Academy Ruins, manlands like Celestial Colonnade, and engine lands like Urza’s Tower.
The one time it comes up is if you try and Tectonic Edge the opponent off of a color, and then have to use Path a turn or two later.
Swords to Plowshares + Delver of Secrets
Delver of Secrets is a card that really wants to be getting in there, and people will even cast cantrips with the sole purpose of flipping it. Delver’s “match made in heaven” is Lightning Bolt, since it can either disrupt or go straight to the dome to take a turn off the clock.
Swords to Plowshares also disrupts, but does so at the expense of adding time to the clock. The life gained will probably require at least one more Delver hit, which is another turn for the opponent to draw an answer and make land drops. This is bigger than it sounds, as most Delver decks are working to constrict the opponent’s resources long enough for a Delver to finish the job.
That said, if you’re playing Delver of Secrets and white in Legacy, then you’re probably playing Swords to Plowshares. The card is simply too efficient not to play, and it beats dying to Tarmogoyf.
Snapcaster Mage + Rest in Peace
This one’s a classic example of hindering your own deck a bit while hosing the opponent’s way harder. I’d gladly shut off my Snapcasters to shut down Dredge or Living End.
Tarmogoyf decks (like Junk) tend to shy away from Rest in Peace, while Snapcaster Mage decks are more willing to take the hit. Part of that is that Snapcaster Mage leaves you with a 2/1 body (even if that isn’t why you’re playing it), and part of that is how the decks are constructed. Tarmogoyf decks rely on ‘Goyf to apply pressure, and they need it to win the game. Snapcaster Mage decks are playing it for value, and the cards Snapcaster would be flashing back are generally useless in the Rest in Peace matchups.
Spirit of the Labyrinth + Sylvan Library
If the opponent has a critical mass of removal, Sylvan Library can help slog through it while Spirit would just die. Meanwhile, Spirit helps the threat count, carries equipment, and hoses certain strategies (you’ve never known true misery until you’ve paid 7 life into Griselbrand to draw a single card on your opponent’s turn).
While Spirit and Sylvan fill drastically different roles, they’re good in the same matchups, but the effects are powerful enough to risk the nonbo. It helps that neither are 4-ofs, usually the split is 1 Sylvan and 2-3 Spirits.
Chains of Mephistopheles plays a similar role to Spirit, and Jund will often have both it plus Sylvan Library post-board because there are too many dead cards in some matchups.
Have I missed any classic, vaguely tournament playable nonbos? Let me know in the comments.