There are six different long-haired breeds. These are:
A sheltie has smooth fur without any rosettes. Its facial hair is way shorter. Shelties have usually satin-like hair that can have a wide range of colors.
A coronet is quite similar to a sheltie with the only difference being a swirl on its forehead. His fur is long, silky and may have any color.
A texel has long hair but unlike to a sheltie or a coronet its hair is very curly. Its fur should be brushed and groomed regularly. Texel guinea pigs only have red or red-white hairs.
The angora has two swirls, one on its forehead and the other one on its backside. Because of the swirl on its forehead, hair is falling over its eyes. Angora is the breed with the longest hair and grooming is required as well. The angora guinea pig mostly has the colors black, red, white or a mixture of these three.
The alpaca is similar to the angora but its hair is curly. This is one of the more rare breeds.
A merino is a mixture of a coronet and a texel. It has curly hair as well as a swirl on its forehead.