I'm sure you've seen these, but probably some have not:
https://www.deutsches-museum.de/en/collections/transport/road-transport/bicycles/j-rad-treadle-bicycle/
https://www.renehersecycles.com/riding-the-first-recumbent/
https://thecabe.com/forum/threads/ultra-rare-1937-glidacycle.151841/