Generally I fill up on the side dishes on holidays and maybe make a little something to go along with them.
Though, there are so many sides on Thanksgiving and they are all so delicious that I don't even bother making anything extra that day. I digress.
I think it is easiest to make a one-dish meal on holidays (unless everyone is a vegetarian, in which case a more complicated vegetarian menu would be in order). Pasta dishes, such as vegetarian lasagna, would work. A quinoa dish or rice dish would also be great options. I have a couple one-dish recipe hubs that are vegetarian and may give you some ideas.
Have a happy Easter!