Antique lithographed tins, made from the late 1930s through the ’50s were originally cookie containers. Most are rectangular and boxy with movable wood or metal handles, but you can also find oval, oblong, and octagonal pieces. Designs are as varied as the shapes: The most common patterns include basket and blanket motifs, plaids, and florals. More elaborate—and today, more collectible—tins feature seaside scenes, playing children, nursery-rhyme characters, and kitchen utensils.

A good reference is Decorated Biscuit Tins: American, English, and European by Peter Hornsby. Or check out Huxtins for picnic tins online.