not familiar enough with libby or the narrators, but here are some fun non-fiction books that aren't biographies, pop psychology, or self-help, but which might have general appeal:

• almost anything by Bill Bryson, e.g. At Home, A Walk in the Woods, A Short History of Nearly Everything, basically just science writing at its best
• 1491 and 1493 by Charles C. Mann, which debunks a lot of the common myths about Columbus, indigenous Americans, and American colonialism. Excellently written, these are enjoyable as well as informative.
• anything by Michael Pollan (I personally find him repulsive in his mindset, but he's well liked by others): The Botany of Desire, The Omnivore's Dilemma, and How to Change Your Mind are all well received

less likely to have general appeal, but which I enjoyed and found important personally:

• The Management Myth by Matthew Stewart, a critique of business and management philosophy. I had no idea MBAs were some of the least successful at running businesses and that philosophy majors were some of the most successful - eye opening and particularly relevant if you've ever worked an office job.
• Disciplined Minds by Jeff Schmidt, a physicist who was fired for writing this book which critiqued the academy for the way it socializes professionals
• A Mathematician's Lament by Paul Lockhart, this book radically changed my view of mathematics as a discipline and unlocked for me me ways to approach math in a way that was enjoyable and productive