Insects have them:
eyes of a house fly. Photo by Sanjay Achara https://commons.wikimedia.org/wiki/User:Sanjay_ach
...and butterflies sometimes have more than two.
photo of a Peacock butterfly by Tony Hisgett https://www.flickr.com/people/37804979@N00
Peacocks are famous for flouncing about with loads of the things, and so does the Argus pheasant:
illustration by T W Wood from Darwin's The Descent of Man
...as do some leaves and types of fungus.
I'm beginning to wonder if I've ever been a day without seeing one.
Spot the Frippet: ocellus. This word is Latin for small eye, from oculus, which means eye.