Salty/fatty seems to be the key. Fried cheese curds/mozz sticks, potato skins, nachos, burgers/sliders, jalapeño poppers, chips w/ warm dips like spinach artichoke or queso dip. Nothing special here but I'm pretty confident these are the most 'popular'. You could always up your game with goodies like maple bacon popcorn or bacon warped cheese studded dates, or maybe a charcuterie board. When done right these items have always wowed me.