Guilds of Ravnica block is the unofficial name for three large expansions set on Ravnica that were released between October 2018 and May 2019. 
Description [ ]
It is not a
block in the traditional sense, because there is no mechanical overlap and the sets are drafted on their own. Blocks were abandoned in 2018 with the introduction of the Three-and-One Model, but that didn't mean that consecutive expansions couldn't be set on the same plane.
The series consists of
( Guilds of Ravnica ), ( Ravnica Allegiance ) and ( War of the Spark ). The first two each are focused on five of the ten Ravnican guilds. They are what you would expect a return to Ravnica to be and it needed to be two to fit in all the guilds.  The third set will focus on the culmination of the  Bolas Arc, the storyline around the fight of the Gatewatch against Nicol Bolas, and not on the guilds. The latter is its own unique thing. 
The following guilds are represented in each of the first two sets:
Storyline [ ]
guilds fight internally between the forces pulling them toward or away from Bolas's influence. In the end, five fall under his influence, and five don't. The five guilds that fall to Bolas all have a planeswalker leading the guild.  Guilds of Ravnica and Ravnica Allegiance are mostly concurrent with and Ixalan so the Dominaria Gatewatch is busy elsewhere storywise.
Guild Kits [ ]
The first two sets are accompanied by
Guild Kits. Each Guild Kit features a 60-card  preconstructed theme deck flavored after one of the featured guilds, combining cards from every Ravnica set released so far. The reprints aren't Standard legal. The Kits are packaged with appropriate pins, stickers, and  spindown life counters. They use the guild symbols as expansion symbols.
Mythic Edition [ ]
Each set is accompanied by a
. Mythic Edition Each Mythic Edition contains 24 boosters of the respective set. Eight of these are specially marked and contain a  Masterpiece card.  Each Mythic Edition uses the same  expansion symbol ( ).
Mega cycles [ ]
Dovin, Grand Arbiter
Lazav, the Multifarious
Rakdos, the Showstopper
Domri, Chaos Bringer
Kaya, Orzhov Usurper
Ral, Izzet Viceroy
Vraska, Golgari Queen
Aurelia, Exemplar of Justice
Prime Speaker Vannifar
Each of these mythic rare legendary creatures or planeswalkers represents the current leader of its respective guild. Guilds allied with Nicol Bolas have planeswalkers; against, creatures.
Lavinia, Azorius Renegade
Etrata, the Silencer
Judith, the Scourge Diva
Nikya of the Old Ways
Emmara, Soul of the Accord
Tajic, Legion's Edge
Zegana, Utopian Speaker
Each of these rare legendary creatures represents a second-in-command or otherwise-important figure in the guild.
Mythic rare guild spells
March of the Multitudes
Seraph of the Scales
Chance for Glory
mythic rare guild spells.
Ten uncommon multicolor creatures, each of whom cost MN and have two abilities, one for each of the guild's colors.
Sphinx of New Prahv
Ten powerful uncommon multicolor creatures, each of which cost two of each of its guild's colored mana.
Each of these rare nonbasic dual lands has two basic land types and enters the battlefield tapped unless its controller pays 2 life.
Each of these common nonbasic lands with the Gate subtype enter the battlefield tapped and produce one of either of its respective guild's colors.
Each of these common artifacts cost , and tap to produce either of its respective guild's colors. For 4 hybrid mana, they can be sacrificed to draw two cards.
Gold mechanical commons
Each of these common multicolor spells demonstrates their respective guild's mechanic.
Common hybrid creatures
Each of these common creatures only have generic mana and hybrid mana in their casting costs.
Uncommon split cards
Depose // Deploy
Discovery // Dispersal
Carnival // Carnage
Collision // Colossus
Flower // Flourish
Consecrate // Consume
Invert // Invent
Status // Statue
Integrity // Intervention
Incubation // Incongruity
Ten uncommon split cards, one side of which uses a single hybrid mana in guild colors and the other side is multicolor. Each of these uncommon cards start with the same first 3 letters in each half's name.
Rare split cards
Warrant // Warden
Connive // Concoct
Bedeck // Bedazzle
Thrash // Threat
Assure // Assemble
Revival // Revenge
Expansion // Explosion
Find // Finality
Response // Resurgence
Repudiate // Replicate
Ten rare split cards, following the same formula as above, aside from the double hybrid mana cost. The hybrid side depicts the guild champion, and the multicolored side depicts its leader. Each of these cards start with the same first 3 letters in each half's name.
Ravnica Inquisition [ ]
Ravnica Inquisition annex set / board game is thematically connected, but isn't part of the block.
References [ ]
Wizards of the Coast (May 18, 2018). " 2018 Spring Announcement Day". . Wizards of the Coast. magicthegathering.com
Mark Rosewater (May 18, 2018). " In the summer announcements video gavin mentions...". Blogatog. Tumblr.
Mark Rosewater (June 12, 2017). " Metamorphosis 2.0". . Wizards of the Coast. magicthegathering.com
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Mark Rosewater (May 18, 2018). " Going back to ravnica is exciting but getting 3...". Blogatog. Tumblr.
Mark Rosewater (September 10, 2018). " Guild to Order, Part 1". . Wizards of the Coast. magicthegathering.com
Mark Rosewater (May 20, 2018). " As you look to revisit ravnica three times will...". Blogatog. Tumblr.
Mark Rosewater (September 11, 2018). " In your guild to order article you said the five...". Blogatog. Tumblr.
Mark Rosewater (September 11, 2018). " So are there only 5 planeswalkers in guilds...". Blogatog. Tumblr.
Gavin Verhey (November 1, 2018). " Building the Guild Kits". . Wizards of the Coast. magicthegathering.com
Mark Rosewater (May 18, 2018). " Will the reprints in the ravnica guild kits be...". Blogatog. Tumblr.
Blake Rasmussen (January 10, 2019). " ". Ravnica Allegiance Mythic Edition . Wizards of the Coast. magicthegathering.com
Blake Rasmussen (September 4, 2018). " ". Guilds of Ravnica Packaging, Promos, and More . Wizards of the Coast. magicthegathering.com
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