Wild Essentials Contoured Eye Mask is my favorite sleep mask. It doesn't lie flat against your face, so no wrinkles or crinkles (or messing up your makeup for mid-day naps!). Lightweight and adjustable with velcro on the back. The Wild Essentials company has many masks, but I like this one, even though it's one of the least expensive!
If you buy nothing else for your sleep, buy this on Amazon.