I used to have a stained glass studio, so I know glass! Clear antique glass, which is somewhat wavy with bubbles/inclusions is a very good & unique choice. Also look into standard reeded glass, which is affordable, machine-made and will diffuse the light passing thru. I have it in several of my pocket doors. You can see examples of reeded glass at most window/glass shops or Home Depot/Lowes. Glue chip, as Havasu mentioned, is a unique choice. I have also done a lot of abrasive etching with sandblasting, PM me for details if anyone wants.