A super performant simple eye shader with configurable options for dilation, iris size etc.
By default this shader only uses one texture for the iris so there is very little overhead for added textures, more complexity be added by using the included normal maps for more definition.
There is also a depth effect which shows a custom image the closer someone gets to you which can be adjusted to your liking.
An eyeball is provided with the correct UV mapping which can just be dragged into the Eye bones for your VRC avatar, using the material on an existing eyeball may require the UV maps be edited to match.
(the heart symbol is part of hte VRC sdk but for whatever reason Unity will only let you add an image to your assets unless they are in the Assets folder, you can copy the symbol_heart from the packages folder)