Modern Affinity deck

Affinity was an artifact-based Modern aggro deck. It is the extension of an archetype which first appeared in Standard when Mirrodin was introduced and has been refined with subsequent sets. Affinity used to consistently perform well in Modern and was considered one of the best decks in the format before the banning of Mox Opal. Since then, the deck has never seen the dominance it once had in many formats.

Affinity gets its name from the affinity mechanic, which original builds of the deck made heavy use of. Although the name has stuck, no cards with affinity remain in most current Affinity builds. Thoughtcast is the one occasional exception.

Strategy
Affinity's overall strategy has not changed since its Standard inception. The goal of the deck is to cast as many artifact creatures as quickly as possible and win through combat damage. To this end, it uses 0-mana creatures in Ornithopter and Memnite and fast mana in Mox Opal and Springleaf Drum.

The payoffs for playing artifacts include Cranial Plating and Arcbound Ravager, both of which mitigate targeted removal by shifting power among the deck's smaller creatures. Master of Etherium</c>, Steel Overseer</c>, and Etched Champion</c> also synergize with the high number of artifacts and can be used to close out games.

Though most artifact lands are banned in Modern, Darksteel Citadel</c> and the pseudo-artifact lands Blinkmoth Nexus</c> and Inkmoth Nexus</c> are not, which means even the mana base synergizes with the artifacts. The Nexi are also evasive creatures, and the Inkmoth Nexus can very quickly kill the opponent with poison.

The deck is also versatile in its sideboard options due to most of the cards being colorless, but having access at many cards that can produce any color with Springleaf Drum</c>, Mox Opal</c> and Spire of Industry</c>.

History
Affinity was so dominant in Standard that it lead to most of the cards that hold up the deck being banned. The colored artifact lands are banned in Modern for the very same reason.

<deck title="Affinity - Chikara Nakajima - Pro Tour Philadelphia 2011"> Creatures 4 Arcbound Ravager 4 Atog 4 Frogmite 4 Memnite 4 Ornithopter 4 Signal Pest 4 Vault Skirge

Spells 4 Cranial Plating 2 Fling 4 Galvanic Blast 4 Mox Opal 1 Shrapnel Blast 3 Springleaf Drum

Lands 3 Blinkmoth Nexus 4 Darksteel Citadel 3 Inkmoth Nexus 4 Mountain

Sideboard 4 Blood Moon 3 Etched Champion 1 Magus of the Moon 4 Mindbreak Trap 3 Torpor Orb

Justin Robb won Grand Prix Brisbane 2013 with the following decklist:

<deck title="Affinity - Justin Robb - Grand Prix Brisbane 2013"> Creatures 4 Arcbound Ravager 3 Etched Champion 2 Memnite 4 Ornithopter 4 Signal Pest 4 Vault Skirge 3 Steel Overseer

Spells 4 Cranial Plating 4 Galvanic Blast 4 Mox Opal 4 Springleaf Drum 4 Thoughtcast

Lands 4 Blinkmoth Nexus 4 Darksteel Citadel 3 Glimmervoid 4 Inkmoth Nexus 1 Island

Sideboard 3 Ancient Grudge 3 Blood Moon 2 Dispatch 2 Spellskite 2 Thoughtseize 1 Wear // Tear 2 Whipflare

A more recent build of Affinity can be seen in the deck Daniel Brouillet used to place 22nd at Grand Prix Oklahoma City 2017. Notably, the deck plays zero copies of Thoughtcast</c> and has replaced Glimmervoid</c> with Spire of Industry</c>.

<deck title="Affinity - Daniel Brouillet - 22nd at Grand Prix Oklahoma City 2017"> Creatures 4 Arcbound Ravager 3 Etched Champion 2 Master of Etherium 2 Memnite 4 Vault Skirge 4 Steel Overseer 4 Ornithopter 4 Signal Pest

Spells 4 Cranial Plating 3 Galvanic Blast 4 Mox Opal 4 Springleaf Drum 1 Welding Jar

Lands 4 Blinkmoth Nexus 4 Darksteel Citadel 4 Inkmoth Nexus 1 Mountain 4 Spire of Industry

Sideboard 3 Ancient Grudge 3 Blood Moon 1 Etched Champion 2 Ghirapur Aether Grid 1 Grafdigger's Cage 1 Rest in Peace 2 Thoughtsieze 2 Whipflare