I just listed three different sizes in green googly eyes.  I have them in 16mm, 24mm, and a whopping 36mm.  I like these eyes because the pupils really do move within the eye for that google effect.

16mm
http://www.etsy.com/view_listing.php?listing_id=11419818

24mm
http://www.etsy.com/view_listing.php?listing_id=11419989

36mm
http://www.etsy.com/view_listing.php?listing_id=11420044

Thanks for looking!!!
Nikole