#5: Knight of the Reliquary
It might seem like Knight of the Reliquary is past her heyday, but she's beginning to see some play again! As demonstrated by Grand Prix Porto Alegre Champion Marcos Paulo De Jesus Freitas, he was happy to include the full playset in order to supplement his Naya Zoo deck with additional beef.
In addition, a handful of players were courageous enough to experiment with a new toy from Battle of Zendikar, Retreat to Coralhelm, including Caio Amaral with his Bant Zoo concoction. Once assembled, you'll be able to extract out all the lands from your deck before attacking for lethal! As Eduardo Borge also shares, turn-three kills are very possible!
Welcome back, KOTR!
#4: Abrupt Decay
Despite having no Abrupt Decays in the Top 8 at all, let's not forget that Jund and Abzan were collectively the most represented archetype in Day 2, a testament of the card's importance and prevalence in Modern. An estimated 20% of all Day 2 players have chosen to kickstart their removal suite with three to four copies of this format staple.
Not only is it a maindeck solution to pesky artifacts and enchantments such as Amulet of Vigor, Cranial Plating and Blood Moon, the fact that Modern is littered with cheaply-costed cards makes Abrupt Decay one of the most versatile and all-rounded kill spells.
Its “uncounterability clause” is also very relevant, and is often a good foil against Splinter Twin and Delver decks who seek to protect their creatures with Spell Snare, Dispel or Negate. Willy Edel also demonstrated to me that it is one of the most elegant solutions to Kira, Great Glass-Spinner!
#3: Cranial Plating
It's not always crystal clear which is the most important card in Affinity, considering how each component complements each other so seamlessly. However, I'm going to single out Cranial Plating for being one of the top reasons that Affinity has been so popular all weekend.
More often than not, Affinity pilots would love to have at least one copy attached to any of their evasive threats in order to shorten the clock. The ability to race with Vault Skirge, hop onto another creature in response to a removal spell or kill an opponent who's gained a lot of life (via Inkmoth Nexus) provides more utility that Cranial Plating's brute force seem to suggest.
#2: Keranos, God of Storms
Who would have imagined that a five-mana card could form the bedrock of a truly efficient transformative sideboard strategy? Since Splinter Twin traditionally has problems against Black-Green deck's Abrupt Decays, there was always the option to sideboard out the combo and try out alternate win conditions. Sometimes, Battleskull and Vendilion Clique were the choices.
Nowadays, you'll want Keranos, God of Storms.
In the past, most Blue-Red Twin players had one in their sideboards but the trend nowadays is to play with two, just like Gabriel Fehr did. Yup, it's that good against the fair decks. Even after the Jund player Thoughtseizes it away, Grixis mages have the option of returning it back to their grip via Kolaghan's Command, which is yet another reason for Keranos' increasing popularity.
#1: Wild Nacatl
Three months after the introduction of Modern as an all-new format, Wild Nacatl was put onto the ban list. Imprisoned for over three years, that ban was not lifted until February 2014. At that time, most players thought it was an overreaction to ban a “vanilla creature”, but this weekend's results have proven that R&D's precautions were founded for and that Wild Nacatl is in fact more powerful than the general public has deemed it to be.
With sixteen copies of Wild Nacatl in the Top 4, it is an irrefutable fact that Naya will remain a force to be reckoned with. You'll never look at cats the same way again, not after Grand Prix Porto Alegre.
They scratch hard, and they're nasty.