We actually didn't use any! Originally, we had the gel cylinders that are common for dessert parties in our BEO but I removed them last minute. I'm not sure why since they were not expensive but I suddenly felt the need to save money, I guess.
I don't think much decor is needed and our guests definitely didn't notice that we didn't have centerpieces.
The table set up was just fine - they put out black tablecloths, the food display is presented beautifully and everyone is so focused on Illuminations (and their VIP view) that it's a really easy way save a few bucks.