hors d'oeuvres ideas needed

If it is a work event, can't it be catered?

Gruyere cheese puffs, spanakopita, mini quiche, or pinwheels depending on your budget.

pinwheel sandwiches, mini crab cakes, potato cakes, zucchini cakes, sausage balls, pizza bites...some would be better hot but can be served room temp

My go to is a shrimp and grits appetizer, but it would be pretty labor intensive for 200. (shrimp and grits appetizer )

I've made these caramelized onion, mushroom, apple and gruyere bites but they can be labor intensive for those kind of numbers as well. A variation is to use the premade pizza crust rolled out thinly, baked in squares with a bit of sweet baby rays vidalia onion sauce, a small piece of chicken, a slice of red onion, and a bit of cheese, and a sprinkle cilantro. 

This whipped goat cheese spread on toast points is WAY more sophisticated than cheese and crackers and is always well received when I bring it to parties. It probably could be easily assembled right beforehand.

Lastly, baked brie cups (I don't have a recipe for these but you could probably easily google) with a topping of your choice. 

I make a lot of appetizers for my book club and these are the ones that have gone over really well. 

I was recently at an event where people are accustomed to fancy hors d'oeuvres - this time, they served pigs in blankets, and the guests stormed those platters until they were picked clean!