The 80,000 Hours Podcast with Rob Wiblin. This is the principal podcast for Effective Altruism and provides very good and thorough weekly long-form interviews on EA and related subjects.
The Mindscape Podcast with Sean Carroll. Weekly interviews focused on fundamental physics and philosophy, made accessible by the brilliant Sean Carroll. The Ask Me Anything episodes are also impressive.
The Joe Walker Podcast. From Australia, very good long-form interviews around economics, psychology and philosophy with a well-informed host. Formerly called the Jolly Swagman podcast.
The Making Sense Podcast with Sam Harris. Weekly interviews on current affairs, philosophy and psychology. Some very good material, though the host talks too much and now less philosophy and psychology.
Philosophy Bites with Nigel Warbuton and David Edmonds. A large archive of tightly-edited short talks with expert philosophers.
The TED Interview with Chris Anderson. A high-quality archive of interviews conducted by an excellent host.
In Our Time with Melvyn Bragg. There is a substantial archive of episodes of the BBC show which covers numerous subjects through one-hour discussions with subject experts.
The Rest is Politics with Alistair Campbell and Rory Stewart. Lively one-hour conversations about UK politics.
Hear This Idea with Fin Moorhouse and Luca Righetti. Interviews on Effective Altruism and Philosophy.
The Utilitarian Podcast with Gus Docker. No longer recording, but archive of long-form discussions about utilitarianism.