Strict vegetarian, 18 years.
Use the various veggie patties you find in the frozen foods case. They are excellent and come in a variety of flavors, pick what you want. The best for this day is the Herb Crusted Veggie Cutlet by both Gardenburger brand and another brand, plus if you can find it the Veggie Schnitzel. I wish I could tell you the brand but they are in white boxes. They have a great crispy bread coating plus a really nicely seasoned patty inside, kind of like a turkey patty would be I guess. I gave them to meat eating friends for years and they all loved them.
I make beans, rice, sweet potatoes, one year wild rice herbed mushroom stuffing, cranberry sauce, veggies, etc. Like mentioned almost everything except the turkey itself isn't meat so just go hog wild with that.
I'm nonconformist so I've even had Chinese for Thanksgiving day, it's just food to me. I'm usually alone for Thanksgiving so it's no big deal, really, no family to feed. If you have friends or family you may wish to get a small turkey breast for them, make a Veggie Schnitzel for yourself, and share the side dishes. This works great for the (sometimes) stubborn 'carnivore' in your life (remember that we're omnivores but too many people have Beef Council on the brain).
I think I have (somewhere) a recipe for non-turkey Thanksgiving day turkey, if you want it...