>>42853730The shiny, large, single color eyes seen on Valerie can also be seen on the fairy pokemon Jigglypuff, Wigglytuff, Alolan Ninetales, Audino, Cottonee, Whimsicott, Carbink, Dedenne, and Sylveon.
"Fairy eyes" can also be seen on the fairy tale girl trainer class.
The only times I could find fairy eyes used on a non-fairy type pokemon were on the Vulpix family and on Beedrill. Even if I missed a lot of cases, fairy eyes are much more common in association with the fairy type. I think it is safe to assume that these eyes have something to do with the fairy type.