Fetish gear and machines could work. Like specialized an hard to find gear.

I really like those J. Peterman "Owner's Manual" catalogs. I get them sometimes and I never order from there but I do like how they are made and I read them (most of the time while on the loo). I think fetish and cool devices catalog like that would appeal to some. With hand-drawn illustrations and mini-stories behind the goods.

I was browsing eBay sex toys section couple of weeks ago and someone was auctioning-off fetish gear catalog from the 80s and it went for over $30.00. It was like hard-to-find specialized gear type of stuff.