For reference, I found these two talks most enjoyable to listen to inspite of moving at a fast pace. The speakers are so engaging, I was riveted and totally focused. I want to discover audiobooks which are similarly engrossing in different fields.
https://www.youtube.com/watch?v=vtIzMaLkCaM
https://www.youtube.com/watch?v=Unzc731iCUY
Basically I just listened to whatever my library had. I did enjoy several classes from The Great Courses, which are now available as downloadable content. The one on the Philosophy of Science was unexpectedly eye-opening for me. You should be able to track down a code for a free month with little effort.
Since then I've switched to podcasts, which are free and plentiful, and available on any topic you could possibly imagine. Between running and commuting I download about 20 hours per week, and each of those comes with back episodes amounting to many hundreds of hours. And it's zero effort: once I've found a podcast I like, new content just materializes. And if an episode isn't engaging, just skip it.
It's working.