more press kit than retail kit, but check out notcot.com
She is always getting really creative kits from brands and companies with cool packaging, unique details, great graphics etc. to pitch a product. Good for inspiration.
Depending on your product though and location as well as retail target, you might want to forgo a physical kit and do digital. A lot of typical press kits these days are going this way.
Ultimately your product should sell itself, you just need to provide the story and background info to allow it do so. If it’s a good fit for a particular retailer and that retailer knows their customers, it should be pretty obvious to the retailer and you won’t need to do an over the top kit.
What kind of product and retail are we talking about? Will be a much different approach selling in to retail a unique designer chair compared to a cheaper toilet bowl brush or a handwoven breadbasket.
R