Last week they were cataloguing was is apparently the most complete set in an American library of pamphlets in the series "Biblioteca Popular Judía." These were short works put out by the Buenos Aires-based Latin American wing of the World Jewish Congress.
I ended up xeroxing a bunch of them for teaching purposes. The Spanish is quite simple, and the booklets will work really well for my course on modern representations of the Spanish Middle Ages: What did mid-century Argentine Zionists think was important about figures like Maimonides and Judah ha-Levi?
Some of the pamphlets were not original portraits of major figures, but were rather Spanish translations of important (if now dated) academic articles in the field. Those are useful to have for teaching purposes as well, to be able to give students more reading in Spanish where appropriate.
There are hundreds of them — I wish I had snapped a picture of them all spread out on the table downstairs. But alas, they're all now in a box in the second subterranean level of the stacks awaiting the day when someone will finish cataloguing them.