https://www.we-energies.com/recipes/default wisconsin electric makes all of their cookbooks available for free going back almost a century.

https://content.mpl.org/digital/collection/histrecipe/search over 5400 free recipes available.

https://archive.org/details/cbk?&sort=-downloads over 12000 ebooks.

https://www.gutenberg.org/ebooks/bookshelf/419 i'm not really sure how many ebooks are in here.

https://www.sunmaid.com/order-booklets-online/ https://site.jiffymix.com/recipes/recipe-book/ sun-maid and jiffy both have an ebook available for free, but they will also mail you a paperback cookbook for free.