People's journeys are different, so what is insight for me or triggers a realization for me may not for you. Transformative experiences doesn't always happen in a book. I will add some non-book medias, but not all of transformative experiences of my life.

In my teens, I was all over the place. I was exploring some existential stuff. I probably could have benefited from talking to a transpersonal psychologist. These were three books that stuck out in my mind from that time:

Ken Wilbur's Brief History of Everything (this is Wilber's Integral Philosophy, and helped me know there are some framework to put seemingly competing paradigms and views into a coherent whole, as well as a few philosophical techniques to get my head out of my rear... somewhat)

James Redfield's Celestine Prophecy (kicked off a lot of things)

Robert M Pirsig's Zen and the Art of Motorcycle Maintenance (I didn't know this at the time, but it spoke to me about what can be beyond subject-object duality)

In my early 30s, I stopped using books and media as a proxy for change and transformation, and journyed. Went through a lot, experienced many things that I had only read about. Lots of peak states. But coming back to ordinary life had proven to be difficult. That started the next era -- of embodying what I had found with those peak experiences in ordinary life.

Chris Wallis's Tantra Illuminated -- lots of view correction for me, helped untangled some things for me, particularly around working. I read this one within my first year of marriage.

Second year of marriage, I might have been able to work, but my marriage at this point was on the rocks. I had this book on my shelf for years and never really read it. When I read it, it was pointing out to me some of the deep stuff on why my marriage was failing:

Glen Mazis's The Trickster, Magician, and the Grieving Man.

This is a critical, honest look at toxic masculinity, and descriptions of alternate masculine archetypes; but not complete by itself, just made me wallow in anger and depression, and self-loathing. I could tell, it did not integrate well with the hard-won personal perspective from all those journeying earlier.

The next book that followed was one from last summer:

Crucial Conversations. (Four authors)

This book was very good to read following Mazis's book. It was very practical advice grounded in psychological research, yet very much in alignment with all the things leading up to it. It wasn't a pancea, but reading this and trying to apply it was probably the inflection point in my relationship with my wife.

In the past six months, I somehow got sucked into the orbit of one particular non-dual teacher by the name of Adyashanti. I usually prefer reading rather than listening, and with Adya, it was the reverse. I mostly listen to his stuff while washing dishes (and that seems somehow appropriate). There are some free podcast interviews with him (on different podcast series), and some of his retreat talks are also available for free. He has some guided meditation.

His talks and his teaching lineage is very direct. By that, I am talking about very directly pointing to the nature of being, of letting the world be _exactly_ the way it is. I don't know what kind of transformative experience you have, but whatever it is, if you're ready for this stuff, his words will speak to you. If you are not, that's fine too.