Casper has a beautiful shade of blue, Burt's are green, Tommy's are gold, and his mother's, Allison, are a very unusual shade of aqua. Which she got from her father, feral Russel. With all the cats I feed around here, I'm sure I've got them all, but blue stands out and is the most rare. I think yellow, or gold, is the most common. Cat's eyes are the most intent, watchful eyes I have ever seen. They seem to focus on your very soul.
I like how Mamanyt1953
put it - "limeade". Four of my kitties - Maple, the boys, and.... oh geez, I forgot I only have four now for a moment Ok, three of my kitties have limeade eyes. Pea-Pea has these big pumpkin eyes.