Hi, Welcome!
Here are 2 pages you can start with….
Be sure to only grab private label rights if you want to resell after modification, and master resale rights, or resale rights, if you simply want product to resell that can not be edited.
https://www.plrdatabase.net/?s=plr&post-type=market
https://www.plrdatabase.net/?s=plr+ebooks&post-type=market
Plan Your Life In Color!