The Ravnica block of Magic: The Gathering features ten different guilds, each with its own unique combination of two colors. These guilds are Azorius (white-blue), Dimir (blue-black), Rakdos (black-red), Gruul (red-green), Selesnya (green-white), Orzhov (white-black), Izzet (blue-red), Golgari (black-green), Boros (red-white), and Simic (green-blue).