Blue eyes on cats that don't have a speck of white.
I believe I have heard of cats that are not white but have blue eyes, but they are also very rare.

* Again! Don't care! I feel like my only problems with blue eyes is that they're only given to cats with importance or cats that are "pretty enough" to earn them. Like let's not forget the many world issues surrounding the "importance" of blue eyes. Other than that, go wild with them. These cats have an organized religion, who cares.