Sorry about being late posting here, didn't notice this one when I checked the other day. Do remember that PodioBooks is more of an archive site for people's podcast books, they don't generally make them themselves. Here's a few sites for people who make the stuff themselves, some of which appear on podiobooks once complete. PodioBooks only accepts completed books.
www.darkerprojects.com
Mostly audio dramas but some good stuff still. In particular try the Byron Chronicles. Some of it has a mild horror feel, very occasional bad language but not usually much.
www.leviathanchronicles.com
Sort of a hybrid book and drama in a way, it's an audio drama with a narrator. Quite a few references thrown back and forth between this and Byron. Strong language is present so you have been warned. Think of it as a more sci fi version of Atlantis in a way. The backstory about the founding of Leviathan itself I found pretty cringeworthy but the rest of the story is well worth it, just grit your teeth through the author mauling history. People from the US probably won't even notice the maulage in any case.
www.scottsigler.com
Books read by the author. Horror with a hard science fiction theme. Extreme and frequent strong language. Extreme and frequent violence and gore. The author's post-episode ramblings, removed from the archived PodioBooks versions, are almost worth it on their own. He has delusions of world domination. I particularly liked the one about him using Ireland as a missle base in case Europe fails to provide the required tithe of hot goth schoolgirls once his takeover of the world is complete.
Also while they're not free a subscription from Audible is a pretty decent deal. For the price of one unabridged commercial audio book you can generally get 3 or 4 months of membership, with one book a month including those expensive audio books. Especially great for Terry Pratchett fans. The address depends on your country of course, there are different branches in different countries. Try www.audible.com and see if you can find the right page for where you are. That's the US site so since the original poster is from Texas that one will work for him.
cx2
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To live by honour and to honour life, these are our greatest strengths and our best hopes.