nostr:nprofile1qy2hwumn8ghj7un9d3shjtnyv9kh2uewd9hj7qghwaehxw309aex2mrp0yh8qunfd4skctnwv46z7qg6waehxw309aexjcn09ejh2tnwdaehgunfvyhxzurs9uqzp5daxvenwv7ucsglpm5f8vuts530cr0zylllgkwejpzvak0x2kqmehusjv implements the .m3u playlist protocol. I have found one playlist made by someone else, so not much used, but it's a good protocol for playlists.
I've been thinking of simply generting these playlists from various podcasts and sources of music, so they are up-to-date and available on relays.