Did you know there are free, instant-speed spells in M15? Okay, maybe not free, but there are spells that can blow you out even when all of your opponent’s lands are tapped. Being aware of these is the first step to playing around them, so let’s take a look at the instants with convoke in Magic 2015.
If you’re trying to keep a particular creature alive (or yourself!), be wary of your opponent’s untapped red and/or white creatures. Stoke the Flames is a premium uncommon in the format, and though cards like Devouring Light tend to be format-dependent, they’re usually at least playable and sometimes very good. One thing is for sure: Devouring Light seems miles ahead of Divine Verdict.
Short of removal, combat tricks are next most likely to blow you out when you think you’re safe. White and red are again colors you want to watch, but add green to the list this time, too. White common Ephemeral Shields doesn’t boost a creature’s stats, but it does blank removal and win in situations you thought were trades. Gather Courage is a little more fair than Mutagenic Growth (especially because it’s uncommon), but should still be respected at all pertinent times.
After Kindled Fury in M13, Weapon Surge in Dragon’s Maze, and Coordinated Assault in Theros, seasoned Limited players should be used to playing against cards like Crowd's Favor. This is, however, the first of this type of spell that can be cast with no red sources open, so be aware of when you should be playing around it.
Chord of Calling is certainly capable of being a combat trick, and though it’s a rare in M15, you will see it occasionally. If your opponent has a ton of mana and/or creatures untapped, you may want to think twice before assuming attacking is in your favor. I heard prerelease stories about Chording for Ob Nixilis, Unshackled, in response to a search effect. That’s the kind of story to keep you on your toes.
The Miscellaneous Ones
Unmake the Graves won’t necessarily blow you out, but it can provide some value at the end of your turn leading into your opponent’s turn. Similar cards didn’t see much if any play in recent sets, so don’t expect to see this one often.
And don’t expect to see Meditation Puzzle at all. Pure life gain spells are generally just plain bad, and this one won’t be an exception. Ninety-nine times out of a hundred, you will be actively happy when your opponent plays this against you. So unless you have good reason to believe it’s waiting in your opponent’s hand, don’t even bother playing around it.
Three white instants with convoke: one removal spell, one combat trick, and one unplayable.
No blue instants with convoke.
One black instant with convoke: a double Raise Dead that probably won’t see play.
Two red instants with convoke: a combat trick and a burn spell.
This makes a total of eight instants with convoke—it's not much to memorize, and if you do, you'll have the upper hand in your matchups.