How can I show off my intellectual curiosity without reciting all the books I've read and sounding pretentious or like I'm listing everything I know

A personal statement, no matter where you apply to, is a chance for you to show off intellectually and prove to the reader that you are curious, ambitious and daring. At Oxbridge especially, supervisors and tutors are looking for a very academic and focused style of writing which will convince them of your prowess in essay writing and dissertation work but more importantly will enthuse them about the prospects of sharing a supervision and essentially debating with you. Your interview and future supervisions (if you are admitted) will essentially be a heated discussion with an expert in your field of study - there is no reason why you should limit yourself and hold back from expressing an original or contradictory idea. Similarly, your personal statement should highlight new innovative thought-provoking ideas that you may have had after reading a book, having a discussion, attending a talk etc... However, from having talked to many admission tutors, they do not want to see you regurgitate every quote you like or every book you've read. The emphasis in the essays I have to write day to day is on what I think and this is what you should do too. I would advise you to think about the '3 Rs' 'Read, respond, reflect’- this is my personal technique to clearly identify my chain of thought. Every paragraph should highlight something that you have read or a discussion that you have had, then respond to the argument or theory presented using your own knowledge and analyzing any points made and most importantly reflecting on the wider implications of your views and broader questions that this has elicited that you hope to answer or discover whilst studying your degree. This is how you will demonstrate your intellectual curiosity in a meaningful manner.