Well, one example could be a villainous frog in a magical forest-themed cartoon. It might have black spots and a green body. Another could be a mysterious witch with a black dress and a green cape. It really depends on the specific cartoon's concept and style.
The reason could be that green eyes are less common in real life, so when used in cartoons, it makes the character seem more fantastical or extraordinary. It can be a way to draw attention and make the character visually distinct from others.
Green cute cartoon characters are appealing because they often have unique and charming designs that stand out. Their colors and features make them visually attractive.