A breed is a type of creature with its own unique sprites in the Creatures series of games - either a norn, ettin or grendel. Each breed takes up a breed slot, so there can only be a finite number of breeds installed per game. (Although, theoretically, an infinite amount of breeds could be created!) There are both official and unofficial breeds for each game, of varying quality - some are just sprite recolourings with standard genomes, while others are fully-fledged projects with new sprites, genomes, accompanying COBs/agents and even whole worlds/metarooms to host the breed.
Looking for a particular breed? Browse the list of breeds!