I LOOOOVE thanksgiving!! No one but me eats entirely veg. I do a little eggs but not dairy. We only have one not veg thing anways and my mom does that part.
So far for sure things are creamy baked mashed potatoes (i make them, put in a casserole, the day or two before, then dot and bake until browned on top). This saves time on the big day.
A couple kinds of stuffing, my favorite is a more classic with nuts and sage. I'm alraeyd starting to bake extra bread to stash dried cubes.
a simple veggie mix, just steamed carrots/brocolli peas with salt/butter since the kids love it simple.
I'm making some kind of chickpea cutlets with mushroom gravy for me, and in to balls for DD (she doesn't eat much non veg either) or maybe in to a loaf. I season it with onion/garlic, mushrooms, sage, paprika, lemon zest, thyme
Stuffed squash, OR a squash and pesto lasagna, i'm probably going towards the latter since i make stuffed squash often
Not sure what else, i'll be adding stuff for sure, it seems my mom and i spend 3 days planning/cooking and we have food for the next week and the freezer!
I make a couple kinds of bread/rolls. Always potato rolls since they are so soft and keep well a day or two, and I make them the day or two before while i make the potatoes, then partially bake just like those 'bake a few minutes and serve" ones you can buy.
DESSERTS, what really matters

Pumpkin pie, I made THE best no bake with a graham cracker crust. It's so hard to find a good vegan one, and I've discovered I MUCH prefer the no bake type
Apple pie, blueberry pie, and pecan pie. My kids and mom and I spend hours literally covering her kitchen with flour (the kids make one ALL their own, fun times LOL)