- Paradigms Lost by John Simon. A lot of these older cultural/writing commentary books don't seem to be digitized, but are absolutely worth reading

- Some older tourism books. For example, I have a little pamphlet book on visiting Yugoslavia, written in Polish.

- Unique/interesting formats. For example, I have a book of "useful words for dealing with capitalists and their markets" that was written in German during the DDR. It has about 2,000 words written side-by-side in 8 languages, including English, German, French, Czech, and some others.

- Older magazines, especially fashion magazines. Very hard to get a hold of or find online.