Picnics:
picnic blankets or other ground cloths

eating utensils - forks, knives spoons, plates, cups, bowls, etc.

serving utensils - large spoons or forks, serving dishes

a sharp knife

napkins

paper towels

can and bottle opener

corkscrew

a small cutting board or portable plastic cutting mat

salt and pepper

sugar and artificial sweeteners

condiments such as mustard, ketchup, relish and mayonnaise

plastic zipper storage bags for leftovers

trash bags for clean up

moist towelettes

water and beverages

ice

charcoal and wood chips

fire starter or lighter fluid

matches and/or a lighter

barbecue tongs, meat fork and spatula

serving platters

baking soda for fire safety

oils, seasonings or other ingredients to create the recipes you plan on preparing

Options:
insect repellent

sunscreen

flashlight

portable chairs and table

camping stove

deck of cards or small games

baseball, soccer ball or other athletic equipment

single use camera

bathing suit

books, magazines or crossword puzzles

portable radio or tape or CD player

batteries for said radio or CD player

apron

flashlight