Sure, you knew about clay tablets, but did you know about clay envelopes? This letter and envelope are in the Museo Archeologico Centrale dell' Etruria in Florence, and have not yet been translated. In fact most cuneiform documents are still untranslated, owing to a world shortage of cuneiform experts. Source.
The city of Oxyrhynchus in Egypt is the site of the biggest haul of ancient papyrus yet found, but it has also thrown up some other things -- like these socks. They were knit using a one-needle technique later found in Vikings burials. They have a split toe so they can be worn with sandals. You can see them at the Victoria and Albert Museum in London.
Jesus and Buddha are a couple of dudes sharing an apartment in Tokyo. Of course they are! This is why we have manga, to teach us these things! Hikaru Nakamura's Saint Young Men is up to volume 11 and has been made into an anime, but it's not available in English yet. But they're talking about it at the British Museum.
Grupa z Polski (1995) by Andrzej Mleczko. Go to the Muzeum Karykatury website and teach yourself about Polish caricaturists. There's an alphabetical index of the artists with examples of their work under the heading Nasza Kolekcja.
The National Gallery of Canada hosted an exhibition of Reformation era German art, entitled From a Mighty Fortress, in 1981. This Cranach woodcut would have fit right in, but the gallery didn't acquire it until 1993.