Return to Ravnica is a block, consisting of
Return to Ravnica (October 5, 2012),
Gatecrash (February 1, 2013), and
Dragon's Maze (May 3, 2013). It's the second block set on the plane of Ravnica, after the
Ravnica block, and again focuses on the multicolor cards and ten guilds of Ravnica.
Return to Ravnica focuses on five guilds: the Izzet League, Cult of Rakdos, Golgari Swarm, Azorius Senate, and Selesnya Conclave.
Gatecrash focuses on the other five guilds: the Boros Legion, House Dimir, The Orzhov Syndicate, The Gruul Clans, and The Simic Combine. All ten guilds appear in
Dragon's Maze.