"The British History Podcast" is also really solid for this.

There are also good ones on Japan, The Crusades, Rome, and the Byzantine Empire although I don't remember their names exactly. They're all variations on "The History of [x]" or "[x] History Podcast".

The history of the crusades one is done by an Australian professor and she's really good. I believe she did one on the Normans as well which was excellent, too.

Really, if you're going with History, I would do a bit of research on how they're perceived and make sure you like the narrator's voice. It's almost always one narrator which is perfect for sleep.

Additionally, I will go out and find lectures from "The Great Courses" series which are pretty well vetted for oratory because the speakers are genuine college professors. Just finished one of those on Balkan history which was really solid.

As far as vetting of podcasts goes, most of them are done by well meaning amateurs, but it should become clear whether they actually know what they're talking about. I'd recommend Hardcore History or Great Courses lectures as a jumping off point and then see about podcasts that are similar in respect for the subject matter.