It's worth noting that the link on the page to the list of pictures contains a mis-transliteration in search of "banbutsu" for "banmotsu" leading to a blank result. Both are possible for 万物, but the prior is more common.
I believe this is the correct link to a full list of the Lost Sketches: https://www.britishmuseum.org/collection/search?keyword=ehon...
Thank you for the correction! I managed to find some, but not the collection as the post OP meant to share.