We always serve a Key Lime Cake, &, depending on the year & what the rest of our menu is, in the past, I've done the following in addition to the Key Lime Cake:
Gingerbread Trifle
Coconut Cake
Chocolate Cheesecake
Red Velvet Cheesecake
Million Dollar Pie
One year, we had a Christmas Brunch, &, for "dessert," I served a Cranberry Tart, Egg Nog Coffee Cake, & Hot Chocolate Tiramisu.
One year, we had a sort of a Louisiana-themed menu (because we were serving fish DH had caught during a fishing trip in Louisiana), & 2 of our desserts were beignets & a bread pudding w/ rum sauce.
And we always have an assortment of Christmas cookies.
For Christmas Eve, I make a Strawberry Pretzel Salad to take to my parents' house & to take to DH's parents' house.