There are many purported types of varieties of the Biewer Yorkshire Terrier. Unfortunately, there is no standard regarding the various categories, the definitions of the different types of variations, or even the proper name by way of breed development. The typical variation of mixed breed dogs is defined by the generational, i.e., F1, etc. The Biewer, however, is not exactly a hybrid even as it is not a fully acknowledged breed, which only complicates matters. Most breeders seek to "grow" their own strain of Biewer according to coat color, bloodline, size, or their favored breed club. Because of this, it may be some time before a comprehensive standard is agreed upon between the AKC and IBC Germany, let alone universally. Some breeders use American Yorkies, some use Yorkie Terriers, and some use two Biewers. All of this and more will significantly affect the generational aspects, the puppies produced, and ultimately the variations.
As for coats, they should all be the same. Ultimately, this dog is produced from breeding two Yorkies with dominant piebald genes. Still, there are some clubs that claim that the Biewer may be different from the exclusively tri-colored Biewers that tend to be universally recognized.
The one variation that is most likely the easiest to identify is the size variety. Designer dogs that seem to be the most in demand are the smallest ones. Because of this, the Biewer Yorkie teacup tends to be size varietal that is the most marketed one. Most breeders of these little Biewer Yorkies have their own names for their teacup puppies.