Hambiscuits-you can get the deli to slice the ham (traditionally country or Smithfield ham) into very thin slices, usually they're made with a small bit of ham tucked into a roll--prepacked Parker house are good, any little soft dinner roll; they can be made a day or two ahead; no mayo or anything.
Cookies. Mini scones. An assortment of crackers with an assortment of spreads (chicken salad, crab salad, etc.) all from BJ's, Sam's, Costco, also have mini quiches that are great and little eggrolls, things like that. Oh, my gang loves the mini eclairs and creampuffs, they come 72 to a tub, frozen, just thaw.
My family always has a cold cut platter with rolls and condiments so people can build a sandwich if they'd like, or you can order a sandwich ring from Sam's that's really nice and feeds quite a few people. Cupcakes are really messy at a buffet type lunch, crumbly and papers all over the floor, better to slice a cake and serve it. Mini muffins are good, too. Someone suggested deviled eggs, that is a staple in this area and they go quickly.