I always used to collect any of those niche trade publications I could - you can learn a lot about an industry from the trade pubs (it's like a microcosm of supply chains and inside information).

Personal favourites were ones specifically for hotel designers, packaged food companies, airline service suppliers, and boat builders.

If you ever want a reminder about the scope of opportunity there is in the world, look for the niche industry magazines. They're a delight.