"Non-standardizable" are varieties with geno and/or phenotypes that do not differ enough from standardized varieties, provisional standards or varieties accepted as unstandardized - or have been decided to belong in this class.
The following varieties are among non-standardizable and therefore cannot be brought in unstandardized varieties: foxes of ticked and shaded/pointed varities; chocolate dilutions of shaded/pointed varities; the chocolate dilutions of shaded/pointed varieties; the chocolate, blue and lilac dilutions of argente; the chocolate dilutions of chinchilla and grey agouti; chinchillated black, blue and chocolate; "stone".
Below some examples of non-standardizable varieties: