I have John Seymour's Self Sufficiency book and a few other good allomenteering/self sufficiency books to grow and rear your own.
I have a couple of good first aid manuals, although I do want something a bit more "beyond first aid" at some point.
A few foraging books, and preserving foods of all sorts books.
Some sewing books, to be able to do more than just sew a seam (I could do a zip if I really had to - but it would look all wrong). And some knitting books.
DIY books to be able to sort out emergencies and also build various bits to help me out.
And apart from the self sufficiency books (some are US ones about building to effectively live off grid), I also have a few Scout manuals and other Bear Grylls type "survival" books - which give me some more knowledge on fires, cooking outdoors safely, building shelters etc.
I haven't acquired them all because I have been prepping, some are from when I had an allotment and wanted to maximize it, I like to craft and want to get better at it, I like to make jam (although I haven't made any in at least 5 years due to lack of time) and bake and cook, and DH and I were smashed when we first got a house and had to do lots like tiling as well as painting etc ourselves.
So it has been a gradually evolving collection over roughly 20 years.