Aggro deck

An aggro deck, also known as an aggressive deck or rush deck, is a deck that takes an 'aggressive' approach of dealing damage to the opponent as quickly as possible, generally through the summoning of a large number of low-value minions and the use of direct damage spells and Hero Powers. Aggro decks rely on explosive damage in the early game in order to surge to victory before the opponent has time to counter them. Aggro decks emphasise face damage over board control, often ignoring the opponent's minions entirely. The most aggressive and single-minded aggro decks are therefore known as face decks, as in Face Hunter.

The aggro deck is the opposite archetype to the control deck, which seeks to control the board or otherwise survive long enough to triumph in the late game through powerful but expensive cards or complex combos. With their small minions and focus on the early game zoo decks can resemble aggro decks, but have a slightly less single-minded focus on damage, preferring to switch to a purely aggressive stance only once their control of the board is complete, or victory within reach.

Strategy

 * Aggro decks attempt to overwhelm opponents within a relatively short game. If a player can survive reasonably well against an aggro deck into the mid-game, they have a good chance of defeating it.
 * Some aggro decks aim to deal sufficient damage using minions during the early game to allow them to defeat the opponent using unstoppable burst damage such as Kill Command during the mid-game. Others (such as Murloc decks) may rely almost exclusively on an army of small minions to overwhelm the opponent; or primarily use direct damage such as Fireball to defeat the opponent regardless of the state of the board.
 * The use of low-cost minions allows aggro decks to put several into play very early in the game, allowing them to take control of the board and put pressure on the opponent to defend themselves. However, a focus on low-value minions can mean that aggro decks find themselves starved of options in the mid- and especially late-game. Card draw can help with this.
 * Aggro decks are often weak against area of effect spells, such as Lightning Storm, Whirlwind and Brawl. These can single-handedly wipe-out a board full of low-health minions, making them one of the best counters to an early aggro deck.
 * Another strong counter to aggro decks is Taunt minions. These can prevent the deck from dealing significant damage early on while also creating a card advantage by trading for several of the small, zoo minions, causing aggressive decks to fizzle in the later rounds.
 * Healing and Armor are the most direct and effective counters to aggro decks. Since aggro decks focus on burst over longevity, increasing the player's Health/Armor total can buy enough time for the other player to make a comeback, or even exhaust the aggro player's resources entirely. Along with Immune effects, this is also the only way to counter unstoppable burst damage from an aggro deck's spells or Hero Power, which cannot be prevented by Taunts or removal.
 * While any class can play an aggro deck, there are a few classes best suited for the play style at any given time. In the history of Hearthstone, the following have been the most notable:
 * Perhaps the most infamous aggro deck is the Face Hunter. Hunter aggro decks take advantage of powerful and cheap class cards, such as Kill Command and Animal Companion, which usually synergize with Beasts. Their hero power Steady Shot allows them to finish off low-health heroes, or maintain cards while still keeping up the pressure.
 * Undertaker Hunter, a Face Hunter with pre-nerf Undertaker, is often considered to be among the most over powered Hearthstone decks of all time.
 * Warlocks can use Life Tap to prevent running out of steam, which makes Zoolock continuously viable. The strategy also includes using cards with painful drawbacks, such as Flame Imp, to fuel a rapid expansion onto the board.
 * When League of Explorers was released, and with it Tunnel Trogg, a new deck to be known as Face Shaman emerged. The deck was mostly outclassed by Midrange Shaman until it got Small-Time Buccaneer and Patches the Pirate from Mean Streets of Gadgetzan.
 * Another deck that was heavily improved by Small-Time Buccaneer and Patches the Pirate was Pirate Warrior.

Rock, paper, scissors
In theory aggro decks beat midrange decks, and control decks beat aggro decks.

Aggro decks are considered strong against midrange decks due to their speed, defeating the opponent before they are able to stabilize. Control decks seek to control the board with a lot of removal and Taunts, as well as healing, and thus tend to thwart the short-lived momentum of aggro decks.

While aggro decks should almost always play as aggressively as possible, there are some exceptions, most common in control decks. Decks using Molten Giant (most commonly seen in Handlock and its variants) can make it wise to hold off damage until lethal is within reach; Ice Block can similarly make lethal calculations important, while Ice Barrier can make it wise to use direct damage rather than character attacks to remove the last few points of Health. Reno Jackson and Tree of Life are two especially powerful counters to aggro decks, effectively reseting the game at full mana, with the aggro player's resources already depleted, but the control player just warming up. Failing to anticipate these plays can lead to the aggro player exhausting their burn, making it often wiser to hold off until lethal can be reached that turn.

Attitudes
Aggro decks are best known for their primary strategy: going face. Because of this, aggro decks are sometimes dismissed by parts of the player base as being "mindless", especially "face" decks that focus almost exclusively on hero damage. This is also not helped by the speed and apparent ease with which such decks achieve victory when successful.

However, high level Hearthstone players have noted that there are certain skills which are often underrated when playing aggressive decks. Minion positioning, the consideration of when to and when not to trade, the ability to maximize damage, and how to set up the final push for damage are all crucial for high level aggro play. While most attacks may be directed at the face, the decision of which card to play and when to redirect effects at minions instead of the enemy hero make face decks as challenging to play as many other decks, and their emphasis on speed at the expense of longevity makes early victory not only a possibility but also their only chance at success.

As noted above, such decks are also far from invincible, and depending on the current meta various counter-decks are usually available.