It is important, also, to read books on subjects of interest to you personally, books that will help you to “man-up” to the current age-appropriate responsibilities God has set on your plate, and “sons of Issachar” books relevant to understanding the times you live in and what you ought to do.1
Of course, the previous post contained snippets of the mass of books available to us in the 21st century church. And a good case can be made for your library to contain: a solid bible dictionary (contains encyclopedic entries related to bible names, places, customs, doctrines, etc.), a reputable bible concordance (which lists biblical words alphabetically and then indicates the passages everywhere the word is found), and maybe a bible times atlas (maps representing the geography during different periods of Scripture’s history often along with the routes taken by various important figures).
See 1 Chronicles 12:32. Only guard yourself against reading yourself down into a rabbit hole. You must pursue “breadth of mind.”