odd goods like you might find in craiglist's for sale section. shared passwords or accounts for streaming websites. books. paintings. collectibles. there are often good deals on any dark net marketplace that pops up. All the way back to Silk Road 1.0.
It just echoes what the parent post said, which states millions of people use darknet marketplaces. they see the whole catalogue whether they go straight to the opioids section or not.
sometimes they even list! lower fees than Ebay. Maybe Ebay and Amazon write those Ask Reddit posts about the "scariest thing you've seen on the dark web" to perpetuate that its scary.
Millions of people know this and routinely check them for good deals, the propaganda machine has failed to make them "scary"