Good visor material​ ?

I'm making sandrock ew version and I'm having trouble with finding a material for the eyes.

Sandrock Endless Waltz has green eyes, doesn't he? You may have some luck just cutting up like a Sprite / Mountain Dew / Seven Up bottle after removing the label to use as the eyes. If you'd prefer something more opaque so that people don't see your eyes, may want to look into some of the materials that people use for Halo helmets. I remember seeing (But don't have) a link to etsy that sells that sort of film to apply to a clear plastic that's very opaque to see into but transparent to see out of. Someone else here may know the shop I'm talking about.

PET-G (polyethylene terephthalate) is fairly inexpensive and easy to work with. It's available on Amazon. You can dye it using iDye Poly. Make sure you get iDye Poly. Regular iDye won't work on plastics.

How complicated a shape do you need? I used PET-G to make the face plate on my daughter's Code Geass Zero helmet using a shop vac powered vacuum forming table and an old toaster oven.