Here's a different take on things!

You might look into affiliate programs at places like CJ Affiliate by Conversant. They do physical products.

I sell physical products through Amazon's Fullment By Amazon (FBA) program by sending product to the Amazon warehouse, and letting them do most of the marketing. I also still have affiliate sales through CJ & Amazon.

Lately some IM products have hit the market that teach using Amazon as a dropshipper, and selling on Ebay. Bought one of them to look it over. Basically it teaches you to list a product on Ebay (at an inflated price over the Amazon price), and then when it sells you by it from Amazon, and use your customers address as the ship to. So you might look at Ebay as a source for niche related affiliates too.