Aggro deck is a Magic: The Gathering term for a deck of at least sixty Magic: The Gathering cards which attempts to win the game through persistant, quick damage dealing. Usually these decks will use small, hard-hitting creatures to win the game.
Aggro history
Early aggro decks were rather slow and usually included both small and large creatures. Aggro decks were generally unable to deal with the far more powerful Control decks. As new sets were released, the relative power of the aggro deck increased. Today, nearly every tournament metagame includes one or two aggressive decks.
Evolving Aggro Archetypes
Some aggro decks are linked merely by their color, but they remain similar enough in style that one may refer to all incarnations of the archetype by a single name effectively.
White Weenie
White Weenie is the eternal aggro deck. The deck uses small White creatures (usually costing one or two mana) and often some sort of blocker removal or board sweeper. It has been played since Magic began, with White Knights and Armageddons, and is still played today, with Suntail Hawks and Umezawa's Jittes, or with Exalted Angels and Mother of Runes in the Legacy variant, Angel Stompy. White Weenie was at its most powerful during the Mercadian Masques block, when the Rebel mechanic allowed the deck to dominate. Another powerful White Weenie incarnation includes when the Tempest block was legal in Standard. The Shadow mechanic and the card Cataclysm helped the deck compete against the myriad of other aggro and Control decks.
Sligh
Sligh was the first example of a "Modern Aggro Deck." It introduced the Magic world to the Mana Curve principle whereby the deck intended to maximize its resources every turn. Like White Weenie, Sligh has gone through multiple incarnations, all of which have combined small creatures with burn and the Mana Curve. The first Sligh deck appeared during the Ice Age block in 1996. The original deck, entitled "Geeba," was built by Jay Shneider and popularized by Paul Sligh. A list may be found here. The most powerful incarnation of Sligh came soon after, with the release of the Tempest set. Cards like Mogg Fanatic, Jackal Pup, and Cursed Scroll combined with Mirage block cards Fireblast, Hammer of Bogardan, and Viashino Sandstalker to make Sligh one of the most successful tournament decks of the era. More modern versions of Sligh have been called "Red Deck Wins." These decks have more control elements than traditional Sligh, and it is debatable whether or not they deserve the title.
Red/Green Aggro
Many color combinations in Magic happen to work well together consistently, and the most aggresive of those combinations is Green/Red. This is an archetype that, like White Weenie, has been around since the birth of the game and is still being played today. These decks usually combine the mana acceleration and fat creatures of Green with the burn spells of Red. Often Red/Green aggro decks include a land destruction component, but these variants are more controlling and less aggressive. The most successful incarnation of the Red/Green aggro archetype came when both the Invasion block and the Mercadian Masques block were legal in Standard. These decks used the card Fires of Yavimaya to give Haste to large creatures like Blastoderm and Flametongue Kavu. Another successful incarnation of Red/Green aggro came when both the Odyssey and Onslaught blocks were legal in Standard. These decks used powerful cheap creatures like Grim Lavamancer and Wild Mongrel coupled with a strong burn component in order to give Control decks problems. The deck had a short run of Vintage (Type I) relevency under the name San Diego Zoo.
Stompy
Stompy refers to the quicker variants of Mono-Green aggro decks. These use dozens of one-mana creatures and as little as nine land. The deck reached the height of its success while the Urza's Saga block was legal in Standard. Since then, the deck has fallen out of favor with tournament-level Magic players, succeeding sparingly in Vintage and Legacy tournaments.
Suicide
Suicide refers to nearly any Black aggro deck. The deck uses Black creatures which tend to be efficiently costed yet have a life-threatening drawback, such as Phyrexian Negator or Flesh Reaver. The most successful incarnation of this deck included cards from the Tempest and Urza's Saga blocks such as Hatred, Sarcomancy, and Phyrexian Negator. The discontinuation of Dark Ritual has severely decreased the power of this deck in Standard. For a while, variants of Suicide were viable in Vintage and Legacy but these seem to have fallen out of favor.
Fish
Blue aggro decks are known as Fish decks, referring to the Merfolk cards that used to populate them before the creature type was discontinued. Fish has enjoyed little success in Standard, becoming viable as a potential answer to the Tolarian Academy-based decks of Urza's Saga and later under the name "Skies" as an answer to the Rebel decks of the Mercadian Masques block. Most of Fish's success has come in the Vintage format, where the counterspells and other disruption available to the deck make it nearly the only aggro deck viable in the format that does not include Mishra's Workshop.
Non-Archetype Aggro Decks
Some aggro decks only exist with a few variations and for a short period of time, due to being based around a specific card (which is not reprinted) or a specific mechanic.
Workshop Aggro
This Artifact-based aggro deck can only be built in the Vintage format, where the accelerant Mishra's Workshop is legal. The deck is based on casting four-mana monsters such as Juggernaut or Su-Chi quickly and reliably.
Cards included: Mishra's Workshop, Juggernaut, Smokestack (some versions), Goblin Welder (some versions)
Stormbind
This is a more controlling version of the Red/Green aggro deck popular when the Ice Age block was legal. Combining the card Stormbind with the card Whiteout allowed a large amount of creature removal, although some versions did not include Whiteout.
Cards included: Lightning Bolt, Orcish Lumberjack, Stormbind, Giant Trap Door Spider
Necropotence
This extraordinarily powerful Mono-Black aggro deck existed while the Ice Age block was legal in Standard. It held such dominance over the metagame that many players referred to the time of its popularity as "The Black Summer."
Cards included: Necropotence, Order of the Ebon Hand, Black Knight, Demonic Consultation, Hymn to Tourach
Rebels
Mentioned above, this was a fundamentally different version of White Weenie. These creatures had the ability to bypass counterspells and gain mass card advantage by fetching other Rebels. This deck was so dominant that the card Lin-Sivvi, Defiant Hero was banned in Masques Block Constructed. Later versions of the deck looked little like the earlier versions as the deck morphed heavily in order to win the mirror match (a game against another Rebel deck).
Cards included: Ramosian Sergeant, Parallax Wave, Lin-Sivvi, Defiant Hero (until banned), Mageta the Lion (later versions)
Gro-A-Tog
This deck combines vastly undercosted creatures with a low landcount and lots of cheap/free spells, most of which draw a card to replace themselves ("Cantrips"). The deck proved to be overpowered in the Vintage format, leading to the restriction of Gush, which provided the deck an easy way to draw cards without paying any mana. The deck has fallen in popularity since that restriction.
Cards included: Quirion Dryad, Psychatog, Gush (until restriction), Force of Will, Brainstorm
U/G Madness
This deck, based around the heavy discard theme of the Odyssey block, was first constructed upon the release of the Torment set which included the Madness mechanic. It continues to be successful in Extended, Legacy, and Vintage today, with only miniscule changes in the maindeck from its original Standard form. The deck uses the Madness mechanic to play spells cheaply or for free, as well as the Flashback mechanic to maximize the use of cards or play Roar of the Wurm for four mana. The inclusion of counterspells such as Circular Logic makes U/G Madness somewhat of an Aggro/Control deck.
Cards included: Wild Mongrel, Arrogant Wurm, Circular Logic, Deep Analysis, Daze (Pre-Ravnica Extended version), Bazaar of Baghdad (Vintage version)
U/G Threshold
This deck utilized the bevy of Green creatures in the Odyssey block that grow larger when there are seven cards in the graveyard. While this deck has never attained the popularity of its Madness-based cousin, it has still won high tournament placings.
Cards included: Wild Mongrel, Nimble Mongoose, Werebear, Mental Note
Goblins
Goblin decks existed before the release of the Onslaught set, but they were casual decks with little tournament promise. Onslaught brought a large number of tournament-playable Goblins to the game, such as Skirk Prospector and Goblin Piledriver. By the time Scourge, the final set in the Onslaught block, was released, the Goblin deck also had access to Goblin Warchief, Clickslither, and Siege-Gang Commander. The deck ended up as one of the top tier decks in Standard, especially when combined with Patriarch's Bidding and/or Skullclamp. The Goblin deck has also enjoyed heavy success in Extended as well, leading to the banning of Goblin Lackey and Goblin Recruiter in that format. The Goblin deck may have also contributed to the banning of AEther Vial in the Post-Ravnica Extended format. Food Chain Goblins, a variant of the deck which includes Food Chain to turn the deck into an Aggro/Combo deck, has been successful in both Legacy and Vintage. Non-Food Chain Goblins is considered by some to be an Aggro/Combo deck as well because of the presence of Goblin Sharpshooter, but it is debatable whether this is "combo" or "synergy."
Cards included: Goblin Piledriver, Goblin Warchief, Food Chain (in formats where the card is legal), Patriarch's Bidding (some versions), Goblin Sharpshooter
Affinity/Raffinity/Ravager Affinity
Debatably the most powerful aggro deck that has ever existed, Affinity is an Artifact-based aggro deck using mainly cards from the Mirrodin block. It uses creatures with the Modular ability as well as creatures that can be played cheaply or for free due to the Affinity ability. The deck combines these with draw spells in the form of Skullclamp or Thoughtcast, pump in the form of Cranial Plating, and direct damage in the form of Shrapnel Blast and Disciple of the Vault. The dominance of this deck over the metagame contributed to the banning of Skullclamp in Standard and Extended and directly led to the banning of the six Artifact Lands (Vault of Whispers, Seat of the Synod, Tree of Tales, Ancient Den, Great Furnace, and Darksteel Citadel), Arcbound Ravager, and Disciple of the Vault in Standard. After these bannings, the deck still exists in a mutated form in Standard known as "Erayo Affinity."
The percieved dominance of this deck over the post-Ravnica Extended metagame led to the banning of Disciple of the Vault and AEther Vial in that format. Affinity has not been as successful in Legacy or Vintage due to the presence of powerful hoser cards such as Null Rod.
Cards included: Arcbound Ravager (where not banned), Arcbound Worker, Disciple of the Vault (where not banned), the Artifact Lands (where not banned), Cranial Plating