I really love WFMU in New Jersey. Of course they broadcast on FM, but they have four live streams (I especially like the ‘Give the Drummer Radio’ stream https://wfmu.org/drummer). Take a look at the schedules - you’ll find lots of music that you won’t hear on mainstream radio, across a wide range of different genres, and all of it is archived so you can listen to past shows and see the playlists for each one. It’s listener supported, so there are no adverts except for their own WFMU fund raising. My favourite shows:
- Continental Subway with David Dichelle, on the Drummer stream, playing music in many languages - https://wfmu.org/playlists/CW
- This is the Modern World, with ‘Trouble’, on the main WFMU stream. Incredibly eclectic - https://www.wfmu.org/playlists/LM
Oh yes, 6 Music is a good one. I notice that Iggy Pop has a Sunday afternoon show at the moment (16:00 UK time), and he’s had several series on there in the past, they just keep asking him back because he’s interesting and has good taste in music. And also on Sundays (20:00 UK time) is Stuart Maconie’s Freak Zone, which has been running for years - so long in fact that when it started I remember recording it on cassette tape so I could play it on my commute to work.
As with all BBC radio there are no adverts apart from their own promotional stuff, and everything is available for 28 days after broadcast via the BBC Sounds website and app - https://www.bbc.co.uk/sounds/stations
I spend a lot of time listening to BBC Radio 3, which is their classical station, but they also have a jazz show 5 nights a week, and lots of other music apart from classical - ‘world’ music, experimental and new music, all kinds of interesting stuff in the evenings UK time. Serious music radio, done properly.