I have also found this archive.org resource to be tremendous. They
have the underlying text recognized so you can search for keywords in
the scans. It makes it very easy to find the page with e.g. a
certain variety on it. Some of the character recognition is not so
accurate so it is not always working well, but often it is extremely
helpful. Also you can download the recognized text only in the .TXT
links, which takes up much less disk space and download time. The
only downside is the scan file size, which besides making the
downloads slow also makes for slow page changes in your pdf viewer.
Here are a few others I found which Claude did not mention. There
are also many others you will find if you search for words such as
apple, fruit, orchard and the like.