Free tool I made, no sign-up or email needed either, no bullsh*t just really good help.
I was annoyed at the lack of options for keyword tools like Amazon keyword scrapers, most were expensive and also sucked, I paid $90 for one and it didn't even narrow it's scraping to the Kindle store, it searched all of Amazon! So I built my own, well paid for one to be built since I can't program well, and also built a simple keyword counter and a nice searchable display for Amazon category keywords. I'm building some individual niche pages (keywords specific to a given niche) and once that's done I'm going to add more free tools/data. I hope this helps and saves some people some cash, I built it for myself but it'd be stupid to not share it. BTW just found this forum because some others I used to use became pretty cliquey, I didn't even know KBoards was bought out I just found out on a Google search for other forums, pretty crazy.
I can't figure out how to hyperlink here (did I say I'm not a good programmer?) so here's the plaintext link:
https://www.publishingwithlove.com/kindle-ebook-keywords-tools-data