What's the RAREST anime?

Strange question but hear me out.

I am looking for something that's not on streaming, and physical copies are hard to find.

I miss digging through piles of DVDs at Suncoast and mom and pop consignment shops looking for anime I haven't seen, basically everything is online now so it's not as fun.

Any good movies or series from any genres welcome, just has to be one or two steps removed from lost media. Thanks.