For gdr20.
Mainboard:
Anger of the Gods- Stops Aggro in its tracks. Takes out Mantis Rider, Goblin Rabblemaster, Sylvan Caryatid and can help you take down Courser of Kruphix and Siege Rhino.
Banishing Light- Only really good option in these colors, for larger creatures and planeswalkers. Can also deal with troublesome enchantments or artifacts.
Chandra, Pyromaster- Helps against Mono Black Aggro. Helps against any aggressive strategy.
Dig Through Time- Theres is definitely a reason, this is played in legacy and modern. It can instantly get you you need, for as little as 2 mana.
Disdainful Stroke- It counters Siege Rhino, and can save you from huge threats.
Dissolve- It counters anything, with Scry 1 as an added bonus. 'nuff said
Elspeth, Sun's Champion- Its a really good win condition. And can also save you from a huge board full of 4/4s and larger, more scarier things.
End Hostilities- Every control deck needs an unconditional board wipe. This is the best we got.
Jeskai Charm- It does everything. Bounces a creature(removal), Finishes an opponent off, or can make all your 1/1 Elspeth tokens 2/2's with lifelink.
Magma Jet- Removal for Rabblemaster, or a small dude. Or just a blast to the dome. Scry 2 Is VERY relevant.
Prognostic Sphinx- Can be a win condition, but in ultimate reality, this can help you get what you need, and find you win condition 3 times faster. Very important.
Pearl Lake Ancient- Really good Win Con. She can't be countered, as well as protect herself, and land (commander). Prowess can definitely be relevant.
Winterflame- OH Mah God. I can't people haven't discovered this little trick. Its great against aggro, and decent against midrange. Its stalls the board for a turn, which can be vital.
card:Resolute-Angel- This can pull you from 1 life to 20 life instantly, very good tool.
Deflecting Palm- Way to good, to not play at least a few. This card not only saves you from death, but turns the game around... for a red and a white...
Sideboard:
AEtherspouts- Dude, as a aggro player, I absolutely hate this card. It completely obliterates any aggressive strategy.
Anger of the Gods- Haven't I already explained this card well enough.
Chandra, Pyromaster- Side in against Mono Black aggro, cause picking off there 12 1 drop 2/1's one at a time, makes a person go insane. Its like the Chinese water torture technique. Drop, drop, drop...
Erase- When did enchantments stop being used? Never. This is especially good against mono black aggro, cause a majority of there creatures are enchantments.
Glare of Heresy- Jeskai Ascendancy, Mantis Rider, Siege Rhino, Elspeth, Sun's Champion. Need I say more?
Negate- Not really dressed for my hyper creature-statured meta, but still good.
Nyx-Fleece Ram- Still just as good as its always been. The wool will never let us down.
Winterflame- This card is the best, like ever...
