Diane Phillips has two books that are entirely entertaining "Do-ahead" recipes (she has another do-ahead book, but it's not entertaining specific). They both have menu ideas for breakfast, brunch, lunch, dinner, and appetizer parties.
Perfect Party Food: https://www.eatyourbooks...rfect-party-food-all-the
I have used "Perfect Party Food" many times - it's by far my most post-it'd cookbook. I had a fancy brunch at my house a few years back for 20 people, and made the "Praline apple French toast" and two different versions of the "Crustless quiche Lorraine," and they were a huge hit, both in appearance and taste. I have made the quiche several times over the years, it's a family favorite for Christmas brunch. I have made many of her quiche variations and have made up my own - one combo that I have noted in my book that I remember was quite good is feta, spinach and chicken sausage. The French toast recipe is actually a pie - the pecans are arranged in the pie plate, and the other ingredients are poured over and when done, you flip it upside down on a platter. It is beautiful, and the smell is heavenly.
Happy Holidays: https://www.eatyourbooks...y-holidays-from-the-diva
This one is out of print, but several sellers on Amazon have it. It has complete menus for entertaining through the year. I only recently purchased it, and have only made one recipe out of it so far, the "Sweet corn, spinach, and bacon breakfast tortes." Not fancy, but easy and good. They would be great for a buffet.
These recipes aren't online, so you will have to get one of the books (I would recommend Perfect Party Food - it has four times the recipes), but if you want to cook ahead for entertaining Diane Phillips books can't be beat.