open to a wide variety.
i just read a book about a navy seal who went on the kill bin laden mission.
i read all The Expanse books (sci fi) recently and before that i read some fantasy. i'm getting pickier about fantasy.
i generally dislike books about "regular people", especially living today or in the somewhat recent past. especially if they are losers or don't do much. i don't like unhappy people.
i prefer books where people do big or notable things (even if the character is e.g. a thief).
i like reading about the important parts of history.
science stuff is good if the book is actually good. but i find it usually has some really bad arguments or explanations. so either i think it's wrong or i don't find it very helpful for learning anything.
philosophy is good if there is a purpose to reading it. i don't like reading bad thinkers for no particular reason just because they are famous (e.g. locke, hume, kant, plato, artistotle, mill, marx, hegel).
i like spies and military stuff but don't know which books are good. might try more kinda randomly.
i read modern politics books but i generally don't like it when the ideas are bad. i read Flynn's book (The Field of Fight: How We Can Win the Global War Against Radical Islam and Its Allies) the other day. it was ok. not that great. he did a pretty good job of being right (by saying stuff he knows and not overreaching). but it was a bit superficial and short, i felt i didn't learn that much due to the lack of detail arguments.
i could read more economics stuff (like ricardo, menger, adam smith, or some of the new austrians alive today) but i don't have in mind a clear purpose of what to do with the info and i don't really expect to learn many good ideas/args i don't already know.
i can read bad thinkers and write criticism but what for? no one's listening. i don't learn a lot from it. sometimes i get interested in some instance e.g. when it comes up in a discussion.
one purpose to reading bad thinkers is to try to understand people's confusions. except who actually read locke or kant or plato or whatever? and even if they did, is that REALLY where they are getting their ideas? nah, at least not directly. even if someone basically believes stuff Plato advocated, and read some Plato, they usually will be totally lost if you criticize Plato. even fans of Plato mostly don't know enough about his writing to follow criticism of it, let alone learn something important and change their minds.
i liked reading some stuff about the people who built the railroads and oil companies and the "robber barrons". and some stuff about steve jobs. maybe there's more good stuff like that. i don't know what to search for though. i have low opinions of a lot of the modern famous/rich businessmen. i'm not gonna read a book about Gates or Musk. fuck them.
i liked reading some books about the history of dungeons and dragons, war games, etc. there's a really long detailed one full of scholarship. i think i got the idea though.
i generally don't like reading about psychology, persuasion, rhetoric, etc, b/c it's confused crap. same with parenting or relationships. it's hard to find worthwhile books on a lot of the topics i write about.
sometimes i read anthology or collection type books. like you get fiction books with a different authory for each short story. or non-fiction with a different author for each chapter. it's good for sampling a variety and then you can try more stuff by authors you like. i've found some fiction i liked that way. for the non-fiction i often find it all sucks.