Some great suggestions here, some I'd like to explore. Looking at Amazon though, I am just astonished how second hand prices are rising. Many of the CDs I looked at are over £30 each. That's too much for me to pay to explore a new artist. Yes I know, I should be on Tidal or Spotify, but I have so much music I don't want to spend all my time exploring new discs.
A few suggestions: Kate Rusby
Cara Dillon, both great folksingers, largely in the genre of traditional English folk.
Jonatha Brooke, an underrated American singer songwriter. I saw her in a UK concert having never heard her. It was one of the best I ever went to.
Shawn Colvin, of course
Sara K, "Waterfalls" on Sockfisch is one of the best recorded CDs I have, beautiful music.