I don't have any foods that are only summer cookout foods. I grill year round and make all the same stuff whether it's winter or summer. As long as it's sunny, I'm grilling! It's much less clean up.
BBQ chicken
Kebabs
Burgers
Italian Sausage sandwiches (I like to use grilled naan bread for the buns)
Steaks
Apple Cider Brined Pork Chops
Carne Asada for tacos or fajitas
Baked beans
Coleslaw
Pasta Salad
Unfortunately the ideal cookout can't happen until late July because that's when the corn is ready. No store bought or even farm corn. Picked and cooked within minutes. Also not possible to totally enjoy a burger because the tomato from the garden is important for complete enjoyment.
Weber Kettle grill
Burgers, dogs, and some kind of smokey sausage
Baked beans of some sort (preferably hobo beans)
Corn thrown in the coals of a fire
Dogs for the kids to cook on the fire
Pasta salad (pasta in some kind of Italian dressing) or macaroni salad (with Miracle Whip rather than mayo)
Taco salad (the stuff with Doritos and french dressing, not a salad with taco meat or chili on it)
Coleslaw
Veggie tray with dip
Pineapple to toss on the grill as the coals die off9
Homemade ice cream
Watermelon and cantaloupe
S'mores
Mountain pies with various pie fillings