A few additions.
Arts & Ideas - Radio 3 podcast covering music, lit, films, and well, the arts and ideas. Revolving presenters, mostly knowledgeable and conducive to interesting discussion and debate, except Philip Dodd, a pompous windbag who derails every show to talk about himself, China or to heap scorn on his guests (particularly patronising to female guests). Says 'marinaded' in every bloody programme. If you can avoid this twat, it's well worth a listen.
Revolutionary Left Radio - US podcast exploring the breadth of left politics. Guests are given a lot of time to speak and expand upon their ideas, rather than the usual interrogative presenter focused style.
Safe For Democracy - Very detailed left history podcast exploring US imperialism.
Team Human - Douglas Rushkoff podcast about protest, politics and tech with a revolving cast of mostly US activists (and some who just like the title for marketing purposes).
The Butterfly Effect - Jon Ronson's investigation into porn is funny, sad, awful and informative.
The Partially Examined Life - excellent US based philosophy podcast. Mostly continental philosophy, and thankfully dismissive of repeated demands from sectors of their US audience to cover Ayn Rand, Jordan Peterson, Sam Harris, Dawkins and all the other 'new atheist' fundamentalists. Just be sure to click off after the discussion before you get exposed to host Mark Linsenmayer's terrible band(s) who play out every edition.
Very Bad Wizards - an interesting philosophy lecturer and an irritating psychology lecturer discuss the intersections between the two.
The Essay - short Radio 3 podcast featuring different essays (often on a similar theme) by a variety of different authors.
The AI Podcast - a podcast about AI, funnily enough. Should come as no surprise that there's a strong right libertarian leaning.