I'm a former retail buyer for Target and worked in the Home Pyramid/Division.
In short, the easiest way to find buyers is to use Linked In. I have a short video on how to do this: https://www.youtube.com/watch?v=ZwbfUMRHiq0. And you can find corporate email formats at www.email-format.com.
Other ways: Trade shows are also effective; you can get the mailing address of retail buyers in attendance plus meet them face to face if they come to your booth. Also, network within your industry. You'll find your peers are wiling to trade buyer lists with you.
But most important in contacting a buyer is HOW you contact them. Don't just bombard them with information about your product. Everyone leads with their product. But the ones that lead with their sales history, current retail distribution and marketing plan are the ones that get responses. Why is this information important? It provides a sense to the buyer for how your product might perform in their stores and takes some of the sales risk out of working with your company.