Not a white cat breed but a white traditional Persian cat, Cristalline – Photo: Dani
There is no such thing a white cat breed – sorry. People search for this…Correction, there is one: Khao Manee! This is a very rare cat breed however.
There are grey cat breeds, however. Grey is sometimes called “blue” by the cat fancy.
There is one black cat breed. This is the Bombay cat. The Bombay is meant to be a domestic, miniature, black panther.
There are cat breeds that have white cats as one of the colours allowed under the breed standard. Two examples that come to mind are the Persian and the Norwegian Forest Cat. A white NFC looks magnificent:-
See more white Norwegian Forest Cats (new window or tab).
And there are cat breeds in which the colour white is noted as important. One such breed is the Turkish Angora. The classic ancient Turkish Angora is white with odd eyes, one blue and one yellow. Here is a distinguished Turkish Angora:-
Photo: twin-otter64 (Flickr)
Hope this helps a bit.