I thought I’d challenge myself to create a Blender shader that could make good eyeballs, and this is the result! With this shader/node group, you can load up a standard sphere mesh and make it into an eyeball of almost any type with only a few clicks.

It’s currently restricted to round pupils only, and it doesn’t do any fancy lens distortion that some other eyeball shaders do, but… not bad for a few hours of fiddling.