CLAMP is a group of anime artists. There are currently four members: Mokona Apapa, Nanase Ohkawa, Satsuki Igarashi, and Mick Nekoi. Mokona-san is the main artist and character creator. She draws the more difficult background, does the zip-tone art, and page layout. Nanase-san is the director, producer, script writer, and scenarist. She's the leader of CLAMP. Satsuki-san is the production coordinator and illustrating assistant. She does a lot of cooking. Mick-san is the art director and assistant. She does the final editing work and draws the SD characters.
Their works include the manga Clover, Magic Knight Rayearth, RG Veda, Card Captor Sakura, Shirahime Shou, CLAMP Campus Detectives, Shin Syunkaden, Cluster, Combination, Derayd, Left Hand, 20 Masks ni Onegai (Please, 20 Masks?), Campus Police Duklyon, Wish, Rex: A Dinosaur Tale, Miyuki-chan in Wonderland, Tokyo Babylon, and X (aka X/1999). Magic Knight Rayearth, CLAMP Campus Detectives, and Card Captor Sakura were turned into anime TV series. X and Card Captor Sakura have movies. Tokyo Bablyon, RG Veda, and Miyuki-chan in Wonderland have OAVS. There are two Clamp in Wonderland music videos, but I've only seen the first and heard the second. Clover and Wish have a few animation clips. Clamp has also done the cover illustrations and a few misc. drawings for Soryuden: Legend of the Dragon Kings.