grey eyes do exist, but they're somewhat uncommon. blue eyes can also look grey in some lighting conditions, because they have no actual blue pigmentation - they are actually clear but the blue color is caused by rayleigh scattering - the same reason why the sky is blue
some people have amber eyes which could be considered yellow. I think amber eyes are very beautiful, probably my second favorite eye color behind very dark brown/"black" eyes
Imo "gray" eyes are just a muted blue tone, and "yellow" eyes are just a light brown
I've always thought I have blue eyes cuz when I look at them, they're clearly blue, but people tell me they're gray, and I never got it, but then I realized my type of blue is like a muted/desaturated kind of blue, a "steel blue" as it's called so now I kind of get why they say that.
Human eye colors are the result of varying levels of melanin which is brown, and the blue/green is some kind of illusion or trick of the light that we see from low melanin levels. Just like blue feathers. https://www.si.edu/stories/when-blue-bird-not-blue
The cool light grey color seems extremely rare, but a lot of people have the kind where after two minutes of looking and trying to decide if they are green, brown, or grey, you would end up calling them grey
Mine are pretty much gray. Or basically the colour of the nearby Baltic sea which is a sort of greenish, sometimes blueish or yellowish gray depending on light, but mostly gray. Most people in my family have these same eyes, they are very average and common here. When I visited the US I got told they look weird and cool, but to me they are just very plain and basic.