Anpanman is actually partially lost
From The Lost Media Wiki
This video contains screenshots from a 16mm film: https://www.youtube.com/watch?v=h3M3jtEbaFY In the video's description, it says that the second pilot version of Anpanman in Japanese was once available on YouTube, and there are Greek and Arabic versions of the pilots online. I was also able to find the online links to the pilots: Greek: https://www.youtube.com/watch?v=q0I2glezPEo (Pilot 1), https://www.youtube.com/watch?v=2_QKeElDzRA (Pilot 2) Arabic: https://youtube.com/watch?v=HRr03CCEmzk (Pilot 1) https://youtube.com/watch?v=2yMlKw1szN4 (Pilot 2) There were also auctions of the 16mm films of the two pilots as mentioned in the description, but both of those are unfortunately over.