X - X-rays (hey, it actually works here with the proper spelling) I am thankful for this wonderful invention, it has vastly improved the right diagnosis and saved many people from additional needless pain.
Z - zoodles, otherwise known as zucchini noodles, spiral cut from a zucchini and used in place of pasta. I'm grateful for them since I try to eat healthy meals.
Oops, I just realized I skipped right over Y! SO SORRY!