Ok so these aren’t technically podcasts, but for an absolute treasure trove of spoken word content, head on over to the Project Gutenberg Wiki, and use their filtering tools to find spoken word content. You can look at the full view, or filter on numerous criteria, so for example the Sci fi content (look for the speaker symbol adjacent to the title). The John Carter Warlord of Mars series for free? Count me in! Do note one issue however – this is all fan produced material and the quality can vary. Some readers are fantastic, others less so, and a couple of times I’ve run into folks who do a decent job but have one of those voices that just grates on you. Preview what you plan on grabbing before grabbing the whole thing is my advice.