Webb Companyhas a great range of kid and adult items used at employee gatherings. One of the best ones for a picnic is the portable fan. These come in battery operated versions, with or without water spray.
Windy City has a great collection of coolers used for picnics, outings and generally any outdoor event. These waterproof coolers can be screened, and many of them can be embroidered, without compromising the waterproof integrity of the bag.