By people with Less Wrong profiles

Rationally Speaking — Julia Galef (last episode: 2021-12)
Future Strategist — James Miller
Second Enumerations — Grognor
The untitled and not-properly-indexed occasional podcasts between Robin Hanson and Katja Grace
The Bayesian Conspiracy — Eneasz Brodski and Steven Zuber
The Mind Killer — Eneasz Broski, Wesley Fenza, and David (Officially ended normal episodes around April 2026 - though there may be some special ones afterwards)
Science, Ethics, and the Future — Brian Tomasik
Conversations from the Pale Blue Dot — Luke Muehlhauser
Tsuyoku Naritai! — Alex Hedtke (last episode: 2019-05)
The 80,000 Hours Podcast — Rob Wiblin
Affix — Brian & Chris (last episode: 2019-01)
Clearer Thinking — Spencer Greenberg
Rationally Writing — DaystarEld

Obviously rationalist-adjacent